Originally Posted by BigLar
My average is then $45/night, and I can keep that up at least until the Megabonus is done (I have use for the points

). Corning is a bit of a haul, but if I want I can get my 75 nights in to retain Platinum and then do the rest of the year in, say, less pretigious accomodations.
Seriously, why?
I agree with your Megabonus reasoning, but why go for Platinum? If all you do is stay at FI what does Platinum get you that Gold doesn't? An extra 5% bonus on 75 nights x $45 x 10 points x 5% comes to 1688 extra points; hardly worth the effort, and time and money driving from Corning IMO.
Yes, I know there are a few other benefits to Platinum; like if you take a vacation using points at a FS Marriott property then you will get the 500 bonus points; or if you pay for a FS property (which it doesn't sound like you do) then possibly an upgrade if you are going in the off season, but the chance for the upgrade is good as a Gold too. I don't see addded benefit of Platinum status over Gold in your situation.
Actually I agree with your first plan to not stay at FI at all on this trip (except for Megabonus reasons). Take the opportunity to start in on another chain's FSP, and take the advice of previous poster(s) to ask other chains for an elite status match.