Coleman makes (or made) a tall version of the EZ-Up, it was just long enough to clear the ends of the 13 ft. Scamp
. Wife and myself would set it up and then just carry it until it was slightly over the camper.
Add a screen tent on the far side or off to the rear and I think you would have a great set up. With some minor things to watch out for.
Avoiding the proprietary trailer modifications has some clear advantages. Price is one, and canopy getting damaged in a sudden storm doesn't leave you with wreckage attached to the side of your camper. Detached you can pick the best size and style for the situation even if it changes. Built on if you find it is a little cramped... what you gonna do? External you sell the too small and buy a larger model.
If you put any of those pop up shelters so the legs are right next to the camper shell be sure you tie it out well and maybe even consider some large pool noodles to slit an put on the legs. Metal legs can really beat up a FG shell given some wind.
Most of these type things will break, the flexible poles that can give such as dome tents use seem to be the ones best able to handle bad weather. Our Coleman shelter weighed 80 lbs. (36 Kg) and frame was made out of steel. Worked great until a wind sheer hit and bent the steel legs, all the stakes and ropes held the heavy steel itself gave out.
Cheap will break, expensive will break, have to find the design or type that has the best track record of not failing. For tents (pre-internet) This is how I arrived at what works, and has worked well for around 30 years.
Bad storm came through, tents wrecked and blown down all through the campground, ours was semi-flattened. Saw three different dome tents still up. Went and bought a dome tent. The poles flexing is the reason it doesn't "fail" it give then comes back up. I have woken up with the side of the tent slapping my head when the wind pushed the tent side in, moved closer to center and went back to sleep.
Screen tent you depend on should be dependable and if it breaks should allow for easy emergency replacement at the nearest big box store that carries that sort of thing.