I think I ruined a good thing... Any tips on what I should do?

I think it was too much too fast. You need to learn to slow down and give things time. After 3 dates, you may have known she loved road trips, but that was too big of a move at this stage. You don't want to look too desparate to win her (or any girl) over. You have to be a challenge to a girl - you don't want to give her all the goodies too fast. Be a confident man - and give the girl all the time she needs to develop into a relationship with you before a bigger move. A girl likes to feel the guy is strong, in control, a bit of a challenge, not desparate for a relationship. Don't do anything else at this point, you have done enough. Don't try to contact her again...let her come to you if she is still interested. If she comes back, go slower. If she doesn't, it's okay - we all live and learn.