One thing I really like about the 19' class C was the very short rear overhang. That would contribute to a good tow setup. The longer class C's generally have a very long overhang.
Actually, I am convinced it could be made to work, with some logical and careful modification. It has a 6K axle under the rear, which is mostly defined by the fact it's SRW. With some work, it could converted to DRW, which would result in the axle itself being rated at 9K.
It has 3.73 gears, and since it's just 2WD, swapping out the gears to 4.30 or so would be fairly inexpensive.
Etc, etc. Bottom line is, it's a "project", and I don't want a project.
Thanks for all the comments, but this idea is a pass for me at this point in time. For the time being grand-daughter will continue to pull to shows with one of the pickup trucks, and stay in motels. The motel bill generally gets billed to the client anyway, so it's not really a cost burden.