Difference in finding camp spot or towing w/ 28' v 30 v 32'?

From what I've seen, my 32' can fit about anywhere except tent or the real pop-up sites. My truck is a F150 Supercrew short bed, so about 1 ft shorter than yours. Might matter for back-in sites lacking on opposite side swing clearance.

I think 34-35' is where possibilities start dropping quickly.

For scouting sites, Google Earth's measure tool is your friend. I use it often, and it's amazingly accurate.