I do take my regular sewing machine with me on trips longer than a week or two when I plan on having electrical hookups (we dry camp a lot too). However I store my machine under the bed which is next to the hitch, the smoothest place in the trailer or in the back seat of the truck. Even there, I find my notions are quite jumbled up in their box that sits next to it. I would not want to store a mid arm or frame at the back of a toy hauler due to the excessive vibration. Is there a place to store the setup near the hitch or immediately above the axles? When you set up camp you could move it to the back for working. Obviously this wouldn't work if you move every day, but it might work if you are staying in one place for a while (snowbird maybe?).
I would second the recommendation to look at a sitdown machine. They pull out of their table easily and don't take much setup. If I was going to be staying somewhere for 2-3 months, I would certainly try taking my Handi Quilter Sweet 16 sitdown. For the trip durations we are looking at now (maximum a month), I just piece on the road and quilt when I get home.
BTW, for those who can't imagine taking a machine on a camping vacation, I really do use mine on those rainy or cold days that seem to come on all my trips. Before we retired, our trips were 1-2 weeks long, generally staying in one place 4-5 days at a time. Now our trips are 1-4 weeks long, and they include early spring and late fall when the sun goes down early. Sewing is much better for me than watching TV. I even have a hand crank Singer 201 that I have taken on long trips where we don't plan on electricity. Now that is an attention getter, sitting at a folding table under the awning and enjoying my work.
Pam