The frame and suspension will probably be the most important thing. Not many TT manufacturers have frames that are good for hard usage. Northwood TTs have the best frames and are independently tested & certified, heavy duty "off-road" and built in-house. Northwood is the parent company to several brands - Arctic Fox, Nash & Outdoors RV. Besides the frame, they are built better overall and have many good features.
The only other frame that *might* be acceptable for harder use is the
BAL Ultra Frame. Not many brands use it. It is used by Lance, Jayco and I think 2-3 others. Avoid the frame built by Li**ert.
If we were to ever get a new TT, we'd be looking at a Northwood product. OutdoorsRV used to have a great brochure that listed many of the features but I can't seem to find it now.