We full time in a fiver and have an old 99 F350 diesel truck. Together, they cost us less than $50k. I'm surprised that no one has suggested a smaller conventional trailer rather than a fifth wheel. You could get by with something considerably cheaper and pull it with a lighter (and cheaper) truck. Of course, there would be less space but it might be a little easier to care for (and pay for). To me, a used rig is the way to go. Let someone else take the depreciation and initial maintenance. Whatever you decide, do your homework and learn as much as you can from others mistakes.
By the way, good luck with the grad school.
Russ