Thanks again for all the added comments fellas. After a lot of reading, I have found the GCWR to be 13K pounds. The hitch they put on them has a 3500 pound limit, so that is the tow limit Thor stated for the vehicle. If the hitch is the only thing limiting that number to 3500, then it could be changed. But I still don't know what the motorhome actually weighs. It has a GVWR of 10050, so I have a feeling this is just not going to work to pull my little trailer
And yes, my two horse bumper pull actually weighs around 5500 loaded for a show. I've weighed it on the CAT scale both empty ( 3650 the day I brought it home ) and loaded.
Just to put all this in context, we also have a 33' four horse slant GN that we pull with our PS dually.
The idea of this plan of the little motorhome was to hopefully have a small self contained unit for close shows where we just take one horse. This would have been primarily for my grand-daughter to use. As it is, she is using the truck and staying in motels for out of town shows. Looks like that will likely continue as the preferred method. At 20 years old, she has turned out to be quite a good driver pulling a trailer.
Back to this 19g motorhome, it is a cute little thing. If they would have put duals under the back, it probably would have been a workable platform, because it would have had a 9K pound rear axle capacity. But as it is, it's a 6K axle ( the tires limit it to that ).
This little thing was apparently made to spec for cruise america I'm guessing. It's no longer in production.