To be honest, it sounds like she really likes you. Maybe she's just shy about PDA (public displays of affection). Also, she seems to get really excited when she's doing something with you. I've seen this before with a lot of girls. If you're doing something with them, say a concert, sport, cooking, whatever, they seem to be even more attracted to that person. It has happened to me many times. If she seems excited about the trip, she's probably really looking forward to going.
But, like you said, it's still early in the relationship, maybe she's a bit nervous about it. I can't say for certain since I've never met her and besides, I'm not the world's most experienced about this sort of thing. Though I can identify rejection from 5 weeks away with (so far) 100% accuracy!
I wish you luck with this girl, she sounds like a lot of fun.