A test drive is not a bad idea, but from experience with several different coaches, DP and gas, an empty coach will not ride the same, won't handle the same, or will be as quiet, as a fully loaded coach. It also will not tell you anything about the handling with a toad.
The main thing a test drive will tell you is if the driver's position and controls are within easy reach, which is especially important if both of you will be driving.
Best wishes with your choice. I've had diesel and now have a gasser and do not regret the decision. They all have good points and bad points but in the long run, the floor plan is the most important. You will spend more time sitting in the coach than you will driving it.