Towing an electric cart with wheels on the ground at highway speeds will destroy the motor. The armature is not designed to handle that RPM; centrifugal force will destroy the windings and the commutator. When the armature explodes, it will destroy the field coils and possibly the case. that could result in the differential ring and pinion being thrown our of alignment, destroying the differential.
Then the tires, which are not for highway use, will likely explode, and all you will have left is a set of batteries (with any kind of luck).
No, the windshield and top are not designed to handle 50 to 70 MPH winds. At low speeds they will be fine, but not at highway speeds.
The lawn and garden shop where I finished out my working career was also an EZ-GO dealer.
Many RV parks and campgrounds will only allow street legal licensed vehicles on their roadways. My ATV is street legal, registered, and has a license plate. Very few golf carts are.