Hi Janine, good questions! My wife and I travel a lot back and forth, think it a matter of survival, as well as an art, and so take it as seriously as Roland Barthes took to sharpening his pencils before sitting down to write.
The Euro costs $1.20, the fancy evening dinners planned by Carl cost 20-30 Euros, lunches 10-15, so I'd plan $60. per day for the power meals on Friday and Saturday and $45. for the rest. Breakfast will be served at your hotel. If I were you I'd pay for the hotel with credit cards, but buy AMEX travelers checks for the meals as we will be eating many meals in large groups and asking the waiters to process 6-12 credit cards is no fun. You know you will spend x per day eating, so bring the cash. Plus, if you buy AMEX checks in Euros, you will probably get a better rate than your credit cards will give you. Nonetheless, you will find machines that take MC/VISA with pin all over the touristy city centers, and I've seen visiters like yourself lose their credit cards in machines and discover that their colleagues are quite willing to extend credit.
Bring a face cloth as the hotels will offer only lots of big towels, and a plastic bag to put it in the last morning. If you like to exercise, bring your swimsuit or running shorts; your hotel will likely let you know where the closest pool or gym is. Bring a half-liter water bottle to keep filled from the tap. I always carry 50 cent pieces for restaurants, in tourist areas, that charge for using the toilet. The German word for "toilet" is "toilette," and this one word with sufficient need and 50 cents will open just about any door for you. You probably know to drink a half liter of water per hour on the airplane, stay away from alcohol on the plane, don't watch the movie but instead put the eyeshades on as soon as possible, and sleep as much as you can on the overnight trip over as the morning will arrive sooner than you can imagine and you need that dark for your internal clock. I bring one of those inflateable pillows and ear plugs, stick my head in both from the start, show up for the plane two hours ahead of time, and do everything I can reduce the stress so that I might actually be coherent and functional and have fun the day I arrive. Build in plenty of extra time. Bring a pair of thick wool socks to wear on the airplane. As soon as the plane doors close look for three free center seats where you might sleep on the floor as keeping level as almost as good as keeping the feet up. Wear loose shoes as your feet will swell. My wife does all of this but thinks the only thing to be done, and to look forward to, is to let some big strong man (me) carry all the bags, open the windows, buy the food, while she takes a hot bath and goes immediately to bed, so that at noon, she can go to sleep and sleep until the next day at noon. Best to travel a day early. No matter how well prepared you are, an no matter the promises of all manner of advertising, the chances are very good you will be delayed. Count on it, and arriving on time will be a wonderful suprise.
Bring layers: a light sweater, a heavier sweater, a thin jacket (especially waterproof) and an umbrella as EVERY conference I've gone to in the springtime in Germany has featured at least one refreshing shower. When I'm travelling long distances to strange places I'm always either too hot or too cold. Bring lots of extra underwear, a new toothbrush, and lotion to keep the face from drying out on the plane. Don't eat garlic the day before. Plan on being searched in the U.S. at least three times, and if you are not happy about that, plan on being searched a fourth time. When in earshot of security people, put all ironic comments on hold.
If you are flying to Frankfurt, the train to Heidelberg leaves from the airport every half hour and costs 22 EUR each way, with a discount if you buy a round trip ticket. The travel time Frankfurt/Heidelberg is 52 minutes, trains leave every half hour :53 and :20. At Frankfurt you follow the signs to the trains at the basement level, but as you go look for the "DB" or Deutsche Bahn sign to buy your ticket.
Everyone who goes to university speaks English well, many of the 70% who do not typically speak it poorly. Many businesses, like hotels and clerks in big train stations put English speakers at the desk, college student waiters speak it, but your bus driver will likely not speak English so well and be happy to take your 2 Euro plus change from your outstretched hand. Some people who work for trains and subway systems just don't like foreigners and tourists and will play dumb: if that happens to you, you can tell right away, so just go to the next station or take the next bus. I suspect Heidelberg is friendlier, by and large, then my adopted Berlin, where the city's arrogance is worn as a badge of honor.
Beware that thumb-sized bus and train tickets need to be stamped by you in machines on the train tracks before you get on the train: regular tickets (about 4x7 inches) will be punched by the conductor.
You need not worry about your personal safety, but don't leave valuables in hotel rooms. The hotel desk will mind your laptop and probably lock up your wallet and passport if you asked them; if you much checkout by 11am but want to leave your bags until the afternoon, the desk will mind them for you, too. There are two more things you should look out for. First, watch out when getting on and off busses and subways: those moments when everyone is in motion, surveillance is obscured, and you have only strangers as company. I've seen purses snatched at the JFK or BOS airports, getting on and off busses, precisely as I have seen them snatched on the stairs going down into the subways here: the sidewalks and platforms are safer, for the eyes are on the street as Jane Jacobs famously said, but movement is distracting, and there are all sorts of criminal gangs who want your passport and credit cards and, like the people on the street hiding the coin under one of three cards, they know precisely when you will be distraced and can make their move: they will snatch your purse, ship it to Portugal by courier after courier, and use it repeatedly before you even know it is gone and have called your bank: they do not want to injure you, they just want to play the credit system. This is not Russia, where you have to worry about a blow to the head. You don't have to worry about the sntaching of purses in cafes, right out in the open, as they do in Italy and Spain, but I would keep my hands or feet on my bags. Most of the violence against foreigners here is to the asylum seekers who are stuck in poor districts next to the skinheads, or if you end up in nowheresville on Friday night when the local boys have been drinking. Breakfast in big fancy hotels can be dangerous, too: don't leave your laptop or purse unattended on your table while you go to the buffet. I don't mean to scare you: as in the U.S., most of the criminals are either already in jail or in elected office! The greatest threat to your health will be the cigarette smoke and the schmalz. The people you meet will see that you are a tourist, will be on their best behavior, and go out of their way to help you. Except when I go to wierd places to photograph, I feel much more comfortable in cities here than I do in many American cities, and for good reason: they are, statistically speaking, much safer: there is less social inequality, more police, and for most of your trip you will be living in a wonderfully protected tourist bubble.
As for your baggage question: I count on 45 minutes from the time the plane lands until the bags arrive at the end of the belt. Mark your bag on all sides with silver or red tape as . I know that only 1% of bags are lost, but many more are delayed: carry your laptop, drugs, toothbrush and at least a change of underwear in the event your bags are delayed a day (happens often enough). Pack anything that looks like a weapon, including your fingernail clippers and nail files. Security on the way back will not be as obnoxious as the U.S. (where they seem to scrutinize your soul), but I would still plan to be at the airport two hours early, if only to reduce stress, and so you might read something you've always wanted to read, like "Design Patterns" by the Gang of Four, or if you are have a life, Christopher's "The Timeless Way of Building:" surround yourself with cotton wool, go into a time warp, buy your way out of discomfort: do everything you can to reduce the noise, thirst, anxiety, of what is a routine, industrial transportation process, to a minimum, so that you will have the energy and presence of mind, once you finally arrive in Heidelberg, to devote to your colleagues.
I hope you find this advice as helpful as it has been to me in writing it! Looking at it now, I'd say I'm homesick!
All the best,
Bruce
