I've got a quick question about safe houses. I want to use/get the NCR safe house to use as my primary hideout. BUT I don't want to help the NCR any more than I have to. If I gain access to the safe house and then turn against the NCR do I get to keep the NCR safe house?

yes im pretty sure

Youve already got the key how would they stop you?

Yup. Now http://fallout.wikia.com/wiki/Gomez_(Ranger) could be a mild annoyance- but getting in and out should be no problem.

I did that with the BoS. Couldnt help but feel bad at that moment because i just waltzed in, Shot Paladin Sato and looted the place

But yes, you can still use safehouses as long as you have the key