Germany....help!!

Hi all!
So I posted about a holiday in Italy the other day but Michael O'Leary made me an offer I couldn't refuse so we're going to Germany instead. Flying into Frankfurt (Hahn) on a wed night and out the following wed night. I'm finding it really difficult to get info on Germany online. I've come up with two options.

1) Get the bus direct from the airport to Heidelberg. Stay there until the Sunday. There's some kind of big firework display/festival there on the Saturday night. Have any of ye been to it? Is it worth going to, good atmosphere? Get the bus up to Koblenz and spend the rest of the time travelling along the Rhine back toward Frankfurt staying in campsites, renting bikes etc. Is it easy to get camping in the Rhine valley? Is there much nightlife in the smaller pretty towns such as St Goar, Bacharach etc? We're not crazy party animals or anything but it would be nice to stay in places where there are other young people to socialise with.

2) Get the bus to Koblenz, do a Rhine river cruise on the Thursday and head to Heidelberg on the Friday, spen the weekend there and then head south to Lake Constance and hopefully camp/stay in a hostel there and work on our tans by the lake. Is this too much distance to cover in a week? Lake Constance is the closest lake I can find to Frankfurt and I think it would be nice to be able to lounge at a lakeside for a while. Again is there much nightlife around there or is it more of a family place?

3) Are there other options I'm overlooking?!

Basically, I have no clue what to do with a week in Germany and I'm looking for some hints or advice. We're looking for a week of relaxing and unwinding days and social nights in a scenic setting!! All help gratefully accepted, thanks a million!

You might want to consider taking the KD-Line ship from Mainz to Koblenz...or get off in St. Goar and then train to Koblenz, and then work your way back to Frankfurt. Or train straight from Frankfurt to Koln and work your way back.

But if you want a relaxed trip, I'd suggest taking a train from Frankfurt down to Stuttgart in Baden-Wurtemburg. From there you should go to Baden-Baden, and enjoy the thermal spas. It's a beautiful area of the country (the black forest). Then travel down to Freiburg...it's considered the California of Germany...a very nice city! From there, it's a short train ride to Basel (bypass) and travel onward to Bern, Switzerland. From Bern you can either explore the Alps or head north east up towards Zurich and lake Constance.

Ideally that trip should take place in the summer...but i'm sure it's beginning to get nice weather too.

I lived near Stuttgart for almost a year and Heidelberg was my favourite place to visit. Loved it! It's picturesque and has a great atmosphere. Lots of students and foreign tourists there. I believe there is an American Base nearby, so lots of Americans. But very cool town. You can meet young people easily.

Your suggested itineraries seem fine to me. It all really depends what you are into. Personally I like #2 better. The landscapes are beautiful in that region, generally speaking.

I also try to avoid big cities, being from a rural area and also from a small populated country I found Germany to be dense no matter where I went there it seemed to be super crowded with ppl. I also don't think it's too much distance to cover in a week, again I'm used to travelling 1000's of miles in a week.

Have fun!