For such an amazingly (unnecessarily) long story, I still have no idea if you went on that hike with her.
You get that you didn't tell us, right? The whole thing built to it and you left it out entirely?
I'm going to assume you did.
Of course she backed off! Jesus, you've been flirting with her for weeks... Dancing around this crap and you finally get her out and you don't make a move.
Seems pretty evident to me what the problem is.
How to re-introduce sexual tension after you take her out on a climatic date that was building for weeks and then you disappointed her? After you've been friend zoned? Invite her over for a movie... And make sure you kiss her.
You could also try kissing her out of nowhere. Friends don't kiss friends.
That's the best I've got for your situation.
And next time --- avoid this and don't shit the bed on your date
Good luck