Any recomendations on a 5th wheel hitch? The trailer is about 5500 lbs loaded.

 

Stick with the big names like:
Reese, Draw-Tite, Hidden Hitch, Curt and Hijacker

Also purchase the application mounting hardware for your specific vehicle.
There are some kits that are universal which will involve drilling a bunch of holes in your frame or welding on your frame which will void your truck warranty.

 

Use these brackets. Very easy to install. Took me about 2 hours to get the brackets installed and the hitch rails. Most often then not the hitch you buy will come with the rails, but you still need this bracket. Worth the $115 to not putz around with the universal one the hitches come with. I would stick with a big brand as suggested. These brackets should work with the '08, but I would double check.

F150 fifth wheel rail bracket