Thanks AZBuck for the usefull information on hotels and trains.
For the personal side ... I'm 29 and drive here in Europe a lot with the car. For you Americans it won't be a lot but here I do 1000 km every week.

As at this moment I haven't got a clue if my flight back will be payed for if I stay an extra month can someone tell me if what to do to not end up in jail? Because if I don't use the booked flight AND/or leave from another city then Washington. I would like to pay a ticket back to europe in the States but is this legal, cheaper and possibel??

To be honest... I want to see everything!
I know it isn't possibel but isn't it possibel to do in 3 weeks all the main cities from LA to Chicago, Boston,... ? The Grand Canyon and Niagara falls maybee also?? I've allready read that to really enjoy the big brother of EuroDisney you should need a week or two ... so for Miami I'll have to come back I guess.

So .... what's realistic?
How much does a flight cost +/- ? Wich are safe but cheap airlines??
I'm also a photographer, but not of profession but I like to make neat shots of scenery, buildings and typical moments.
I like history so good musea would stick in good also. And most off all I like to see the buildings I see on TV and in the movies for real. (NYC was allready amazing, now the rest)