Western Europe Tour

Hi. I have got this sudden urge to plan a driving tour of western europe and would like some information on the same.
1. Which countries can be covered conveniently (leisurly pace) in 2-3 weeks
2. Which place would be a good starting point
3. Any suggestions on the route to be taken
4. How much would renting a car cost
5. Planning to stay in youth hostels/B&B along the way so recommendations
6. Right time of year (month) to travel across Europe

I know the entire thing is currently vague and not structured but its just a thought that I want to execute.
Thanks

IS this just a desktop plan to keep ppl. busy - or are you coming (money in the pocket? time off?) ?

1: You cannot "cover" any coutry except the very small ones (Luxembourg etc.) in that time. But you can make a good first visit to 2 - maybe 3 small ones (Belgium, Denmark, Netherlands, Austria) - or see a part of one of the big (France, Itlay, Spain, Germany ...).
If you travel constantly you can PASS most of the 35+ countries (visit the airports or trainstations - or look from the car windows) - all are worth a few weeks visit.
2: Any city you would like to visit - or where you can fly into cheaply and which isn't too far (in time and money) from your final destination.
3: Find out what you want to see/where to go - and grab a map! And tell us HOW you will be travelling.
4: Europe in not a single country. Get the idea by simply going into the homepage of Avis or Hertz!
5: There are several 1000 hostels, 10,000s of B&B in Europe - do you expect ppl. to gnenerate lists of those they like for a whole continent?
6: late spring - summer - early autumn

This question is way too vague. You need to decide what you want to see and narrow things down a bit. You can see a lot driving in 2-3 weeks, but it depends what you are interested in doing and seeing.