Options for adding AC to FG campers that have accumulated in my brain.
- Reinforce roof top and mount there. Could be ribs, "saddle" or other fairly extensive modification. But is pretty much required. The roof is factory modified for roof AC because it has to be to support the weight.
Window shaker AC units.
- Inside existing closet or cupboard. Stock location on many scamps. Requires cutting wall to install vent panel for exaust air. AC is totally inside camper in most cases.
- Window mount. Many approaches used to support AC unit.
- Through the wall under rear dinette (bumper support)
- Through the wall center front. I only recall this one specifically from a camper having a front dinette mod instead of a bunk. (tongue support)
- And people have added 4 inch hose hookups to camper and put a small AC unit on the ground outside with covers that allowed hooking flexible dryer hoses to trailer.
You probably don't need over 6,000 btu for a 13 ft camper. Those can be had for under $150. And come in a very small package. Roof AC unit is $500 plus.
Rear wall under dinette seems like it would be the most stable and uses less inside space than in closet/cupboard. Will reduce tongue weight a bit, don't want that too light
or sway becomes a problem. With a remote control should be easy to control. Air blowing at legs could be chilly but for sleeping seems good. Spare tire storage could be an issue. Move to front is a possible solution.
Closet/cupbord with vent in the wall might be a little more flexible in terms of replacement unit sizes when compared to an opening cut in wall to fit specific unit. And provide better air distribution. Given a choice between cutting the wall and adding an "new" fridge
vent panel vs dropping 75 lbs on the roof I know which I would pick.
Using hoses with AC on the ground is pretty creative, and you can use AC unit in a house when not camping, but one does have to haul the loose AC unit along if one will need AC that trip.
Window mounts range from mount on board and close window on it to some pretty sophisticated mounting solutions.
People with fantastic or maxx air power fans point out that in a small camper it really helps keep it cooler. Those with them love them, those like me without have dreams of someday.
Hope this helps you decide what will work best for you. I would think long and hard about the work required to have roof mount. And how much I could count on it not causing sag or breaking long term vs some other solution that will keep me comfortable in the heat.