Bill, I have used the Purpleline trailer mover since 2014. My driveway has a decent slope, but these motors saved me several headaches parking. On some sites, I've disconnected and drove the camper into the site, hitch first, so my door points to my neighbor which is normally a friends site. Basiclly I'm parked backwards on the site.
It does have a grade limit, I want to say anything steeper than 6% it won't move the trailer, or the motors start slipping. I've had that happen when parking in my driveway, so I get it angled to where the slope is minimal and it doesn't slip. It survived a tire blowout in 2017. So the motors are fairly tough.
There is a weight limit, the customer service folks can give ya up to date info.
I didn't install the system, a friend did. The left motor was snug next to the left motor. Since I'd removed the Electra toilet, I then decided to remove the drainline. You may have more room, where there's no interference with your toilet drain.
Since the motors turn the camper wheels, the camper moves itself. The only hiccup is with soft ground, the touge wheel sinks.
It has a very sharp turning ability, when running the two motors in opposite directions.
Pictures are posted in my album. Good luck with your decision.
https://purplelineusa.com/product/en...-motor-system/