Again, from my experiences I would say no vacation and don't be hot or cold- be neutral.
My wife and I went on a great anniversary weekend two months ago. We had an amazing time, connected like we hadn't in months, plenty of affection (including sex a few times) and I love yous.
One week after we returned, she was back to wanting a separation/divorce. Trust the process and enforce your boundary- as painful as it may be.
As far as being her friend: are you capable of being just a friend right now? Without hopes/expectations of something more? I know I was not and am still not.
Me:38 W:39 No Children BD: 5/13 EA/PA Confirmed: 7/13 W Moved out 12/13