sounds like a really interesting case...
the RA position might give you some real experience and open your eyes to something you could really see yourself doing, or what you really never ever want to do again...learning experience...
having said that, i don't think you should delay the grad school any longer, you got that masters in math for a reason, and you dont wanna be in grad school throughout ALL of your 20s
and since i think i know who you are, I think you should apply to all the top programs you want...because that one good
LOR will help...a LOT
as much as I would like to kick it with you for another 2 years, you need to get outta here and go to cambridge