Another question I have is that I have never really rode massive ammounts of powder. Not to sure how my board will handle it, Im 5'5 and I ride a 147 Skate Bananna should I pick something bigger up?
How much do you weigh? Regardless, a 147 isn't going to be a great powder board, but the rocker helps it float a little.
I wouldn't buy a board for powder just for this trip unless you really think you'll use it at other times as well. Especially since you don't know if there will be massive amounts of powder when you're there.
Worst case scenario, if you board isn't cutting it, you could just rent a nice board for the days that you need something bigger. You can get a pretty good board for about $50 a day which is better than dropping $500ish on a board you may not need.
There are also places to demo boards so you could try that as well.