I flew into and started from Frankfurt am Main. I spent a couple of nights at the Frankfurt Youth Hostel (they are for all ages now). Went down the Main (pronounced Mine) river to Wiesbaden and spent a couple of nights at the youth hostel there. It took me a few days to get adjusted to being half way across the world. The youth hostels cost a little over 50 bucks a night (for a potentially shared room) and include breakfast. They cost half that in Belgium and France. They are a little egalitarian, which I like, if you're not familiar with them. They can be kinda fun because other bike tourers, packers, riders and travelers frequent them.

Then I started staying at campgrounds on the Rhine river. They were about 15 to 20 bucks a site and seemed like there was one every 10 to 15 km. They say the best part of the Rhine is between Mainz and Cologne. My advice is to try to do the minimum amount of miles a day so you can sit on the banks of the Rhine, watch the transport ships motor by and sip on a beer or two in the sunshine. It is an incredible way to while away the afternoon and soak up the vibe. The campground in Koblenz at the confluence of the Rhine and the Moselle rivers is nice. The fortress on the bluff is worth a visit. There is a youth hostel up there as well.
I only went to Cologne and then headed towards Aachen and Belgium.

I'm starting my 6th week over here, living on my bicycle. If you have any questions don't hesitate to contact me.
Larry