Since you already have towing experience, moving up in size should not be an issue. By adding up to 10 ft of length and lots of additional weight, what may be an issue is the size of your tow vehicle. You may need a new truck to go with the larger rig.
Pulling an oversize rig with an undersized truck can take all the fun out of a trip.
The height is not an issue. Most primary & secondary roads are built for 18 wheeler trailer heights, well over most RV heights. You'll find a few older roads not built to the current specs with lower clearance, but they're easily avoided. All the low clearance locations are listed on some internet sites and in any truckers road atlas (and some GPS units).