DANG; THAT is an excellent price for a whole strip loin! We've done whole strip roasts the same as a rib roast with just as great of results. I love 'em! The only thing to keep in mind is a strip has a strip of gristle in it (same as a T-bone, since one side of a T-bone is the strip).
1) Don't go cutting the fat off of my steak, please!
Seriously, I wouldn't trim ANY of the fat cap off. Leave it on as it adds flavor. You can always trim it off on your plate if you don't want to eat it.
2) I would definitely cook it on your pellet grill. You can't beat the flavor!
3) We cook them in our MAK anywhere between 250° - 275°. After doing several, I prefer 275° - plenty of smoke still, doesn't take too awful long, and it gets a good enough crust that you don't really need to sear. The MOST important thing is to be absolutely sure to LET IT REST for a good minimum 30 - 35 minutes, tented with foil (tented, not wrapped) before slicing it.
4) At 250° - 275° it will take around 2 1/2 - 3 hours. DON'T forget the rest!
Here's one we did a few years ago, and here's the post with more pics:
Whole N.Y. Strip LoinDid I mention to be sure and let it rest?
Cliff