Time to install tires on my truck camper setup

I wouldn't go any wider than 295s on stock 8" rims.
Sipe them if you want or need better traction in the snow. Don't sipe the outer rows of treads, just the 2 or 3 interior rows. They may wear quicker on the back if you put in a lot camper miles. The Firestone MTs I have currently don't seem to be wearing more but they're hard tires and had no sipes so may help a bit with them.