I did a trip a few weeks ago that basically went like this:
Ashford GB (overnight stay)
Calais FR
Yves BE (Brunch, WWI memorial etc)
Luxembourg LU
Strasbourg FR (Overnight stay in Ibis hotel)
Basel CH
Lucern CH (Stopped for lunch)
Como IT
Milan IT (outskirts - snack)
Menton FR (on coast 5km from Monaco just across the FR/IT border - stayed here overnight in Best Great Western - good rates)
Monaco MC (breakfast)
Vieux Port, Marseille FR (lunch)
Barcelona SP (dinner and overnight stay - stayed in Travelodge, completely in the middle of a new development, not many people around but close to airport and cheap).
See the route map here:
http://g.co/maps/yzs4u
I did all this in 3 days as had to get to Barcelona Airport for a flight so was just driving really but great roads and actually fairly toll-less (except the Swiss annual road tax you pay when entering the country) until you hit Italy/French Riviera/Spain.
Approximate cost was about 80-100 euros a night and that was for 3 people... we used hotels.com and booking.com iPad apps to do all of our bookings and usually did it on the way using a free McDonalds wifi point.
Good luck.