Soy cuts to the heart of the matter every single time.Walk in her taking a shit. Then with a completely deadpan face, say, "I love you, girl." Then immediately walk back out of the bathroom.
Eomer, you haven't really said it too much, but the few times you've talked about it more in-depth, she definitely sounds like the kind of girl that thinks she is playing above her level and doesn't want to scare you off. I could be just reading it wrong, but that's kind of the way you make it sound to me. I think she might wait forever if you don't say it first. You obviously do love her, and I'm guessing she does too, so just fucking say it already. You're tap-dancing around it far more than people normally do at the beginning, but you're way past the point when it should have already been said.
I know that there's the whole "let the woman say it first" thing and a million other do's and don'ts, but you've already "established your value" or whatever. She is into you, she has a key, she loves you, she's just scared to say it for whatever reason. So just say it, get it over with, and move on. I would bet your paycheck that she says it right back, and is relieved that it is finally said.
EDIT: Oh, and stop trying to make everything happen on specific trips or outings. Sitting on the couch together watching Shark Week, and she says how much she loves watching seals get ripped apart by Great Whites? "You know, you're fucking awesome. That's why I love you babe." Make it like it has been said a million times before and this one is no big deal.