So, either way you go, you are going to have to purchase two vehicles.
A TT and an appropriate pickup that you could retain and continue to use once you finish this trip seems to make more sense.
Why not look at a fifth wheel since the wife is apparently wanting something a little more "upscale" than what the TT can give her. Take her to look at some nice gently used fifth wheels, get yourself a used 3/4ton truck. That should run you about $65-75K. When it's done, you can resell the fifth wheel and recoup much of that money and keep the truck. A gently used Class C will run you close to that, plus you then need to get something to pull behind it. You will have added several K miles to the MH, so you will not recoup most of your money on that, plus then you will also need to sell the towed vehicle.
Yes, it is convenient to be able to use the restroom when you are underway, but that doesn't negate the fact that it will cost several grand more money if you go that way.
We just pull over and hop back into the fifth wheel for a bathroom break. Whomever is driving needs a bit of a break, too.
