Of course it can be done. You will obviously have to move the wall to the rear of the toilet to allow for the additional bulk of the tank that the new toilet will have. Drain the tank before travel. I'm not sure how well the flush will work with the small vent tube that the black tank now has.
But with each new problem to such a modification, there obviously is a cure.
Perhaps a visit to a Camping World or dealer could provide you with an alternative to an easier transition to a RV toilet that looks and feels more like the residential type???? Just a shot in the dark here.
