It is not easy to know what path to take. Just be true to yourself. If you help her with stuff I think that is OK as long as it is done just for that with no expectations. I also don't see any reason to not be friendly.

I would definitely not be fully available though.Be busy doing stuff. Why not mention the trip. Not to rub her face in it but it does show you are thinking of YOU.

Don't mind read.

All the best

R 25 years
M 14 years
S11 & S13
Working on it alone since Oct 2014
M in trouble a lot earlier (~2 years)
Feb 2016. 1st R chat in a yr.
Next R chat Aug'17
Still together