As you've probably noticed by now, suggestions vary wildly on this subject - everyone travels in a different manner, and options in Europe really are limitless. You can't add on all these options that we're giving you - you'll have to make a choice between them (or find your own alternative way).
The main thing to remember: You can't have a "balanced trip" (e.g. a bit of everything in a way that does it all justice) in just three weeks. You have to make a choice. Either you see as much as possible, visit multiple countries and spend a significant part of your time just getting from place to place, only getting to touch the surface of the places that you see (in which case a tour might be worth considering, as they're good with organizing and getting you to all the right points to take a snapshot before moving on) - or you travel at a slower pace, immersing yourself in places, and will have to stick to just four or five distinct destinations (where "destination" means "city", not "country"), but do get to form the start of a real impression of what life is like there.
I think the tents + cycling idea is great for really getting to see the landscape you're passing through and coming upon unexpected sights and experiences, but I personally wouldn't travel that way, and since everything else is new for you as well, I'd probably personally advice against it for this first trip.
Oh, and a "sleepy village" is the type of village which you won't find in any guidebook or tourist brochure - where life moves at its own pace, same as it's done for hundreds of years. Where there isn't any tourist attraction to see, the age-old church happens to be a particularly uninspiring example and the local teenagers are bored out of their skulls, but where, if you sit yourself down outside at the one cafe it boasts, you can over the course of a few hours observe something of the grain of life and will remember the feeling of the sun and the sounds of the cowbells for years to come (or will be equally bored out of your skull as the teenagers - that's the risk you run).
[ Edit: Edited on Dec 22, 2008, at 2:12 AM by Sander ]