In that video, wouldn't a couple of 2x10s raise the wheels enough to lift the back end of the trailer to get it in and out? We had to do that with our pop-up to get it up our driveway from the "gutter"-like transition from road to sidewalk.
As for the casters- I'm pretty certain I'm going to buy and install them. I'll make sure they're no lower than the rear-most stabilizers. After destroying a set of electric stabilizers back in January- the rear of the camper took the brunt of the force anyway, what's different it it rolls on wheels?