Pay close attention to the towing specifications for those vehicles rated around 3500 pounds. I've been shopping in that category, and have learned it is not as simple as maximum weight I can tow.
They often have a second restriction, on trailer frontal area, that goes with that weight rating. It may be a number (like 30, 40 or 50 square feet) or something general like "does not exceed the frontal area of the towing vehicle."
You also need to fit the tongue weight into the payload of the towing vehicle, and not exceed weight ratings for either axle.
These restrictions sometimes rule out lightweight, full size TTs like Sportsman, Amerilite, Jayco Swift, Lance, and even the R-Pod. The frontal area limits often put you back into collapsible RVs.
I also keep trying to figure out what downsizing might gain me, and see things like "maybe I can store it in the garage" or "10-12 mpg towing instead of 8 mpg driving the motorhome" but neither one works financially against the cost of a new RV and a new small tow vehicle, over any period less than 10 years. So it just comes down to "I feel guilty about driving (in your case, pulling) this bigger house around when I no longer need all the space."