I'd lose that line altogether. I have two filters on mine (3 if we count the big one down under the cab) and none of them has a return line on it. Never had an air issue after filter replacement, I just prefill them then use the Schrader valves to purge the air. Mechanical lift pump too.
Tires, yours are the same size as mine. Actually mine are even wider than yours, the front ones at least. Same diameter tho. Reason I asked is the lip of the front fenders seems to be quite close to the tires tread... Must be the truck riding lower than I'm used to seeing. No matter, as long as tires sit straight vertical and not like /--\ then you're fine.
Pressures, I run 80psi in my fronts year-round. Makes for better handling, and I think less wear. Rears I run at around 65 psi when empty, and I up them to 80 psi if I'm gonna be testing out my rear suspension under heavy load. Car on a bumper-pull trailer shouldn't put more than 600 lbs weight on the tongue, which translates to less than 1000 lb on the axle. That's not much at all, definitely does not require going up to 80psi on the drive axle. May want the steer axle at 80 psi tho, just to stiffen it up some to make it more responsive to the driver. Best I can suggest is play with the pressures and see what you like most. Obviously don't go below what Ford wrote on the door sticker, or above what's written on the tires.
