"If it's Tuesday, it must be Belgium"

I happened upon it last week, ad it still made me laugh!

I'll put in a vote for bike tours - you get to meet lots of other people, many probably in your age bracket - and you get to see a lot of sites in a short amount of time. I think you would be better off looking into hostels for accommodation as you'll definitely meet people who have the same motives as you do.

Yes, I was going to suggest hostels as well as you'll likely meet like minded visitors there.