Is your intent to just have a gutted TC?
The questions you ask require a little more info. The gutted TC would probably weigh anywhere from 1000 to 2000 pounds, depending on the TC. There are some that could weigh less. After gutting the TC, you then need to find its center of gravity, front to rear. This is the first step in determining the trailer length. In my opinion, you would best be served with a tandem axle trailer, due to stability.
As cheap as possible, would be to simply buy a small travel trailer, as previously suggested.
Wayne