I owned one many years ago that was exactly like you are planning. A friends father rolled the TT and wrecked it so he stripped it to the frame and made a flat deck out of it.
After buying it from him I redid the deck and bolted a series of 2X6's to it for a new deck. I worked very well and I used it as a small car trailer. I hauled scores of small cars on it all over the place. Small cars like Austin Minis, MG's, Morris Minors etc. I once hauled my fathers Mazda GLC from Cranbrook BC to Penticton BC over 2 steep mountain passes. And with no brakes.
It worked flawlessly and never had any issues with it.
I say go for it and use the thing.
