Would steer clear of that deal. Seen this many times while living in another state.

We have dealt with this before, a few times and the cabins were on skids.
We had a guy move a cabin onto the lease about 15 years ago, it was on skids and could be moved if it had to be. When the member left the lease he offered up the cabin really cheap because he didn't want to move it. The next guy loved it, it is much nicer than a travel trailer. After five years that guy left and the same thing happen, it was for sale cheap and several people wanted it.
The cabin I stay in at my brothers was the same way. It changed hands a few times and then my brother bought the land and negotiate a cheap price on the cabin (also on skids). Now I stay there.
As long as it is portable (on skids) and cheap enough to move if you need to I am sure it will beat the heck out of having a travel trailer.
But being on skids has not made a hill of beans difference, they have never moved. I think the idea that they can be moved is what makes the situation work.

Simple has it the I have experienced it. The guy putting in the new 16 x 40 has to also install some sort of septic and no, he won't be allowed to jack leg a 55 gallon drum. Running water over there is gonna be some fun.

Please forward the guy's name and number to me,,, I have a bridge I"d like to talk to him about buying.