I tow a Smarty 4 down all the time. Put 11k mi in tow mode this summer. I made a plate that keeps the shifter in neutral and the key in the proper position for towing. Have a Ready Brake for additional safety but in most juridictions the brake is not necessary from a legal perspective because of vehicle being less than 2000lbs. My RV in Smarty Tow mode met stopping distance requirements without the Ready Brake also, but where I can be more safe I choose the safer route.
If the 2 seat Smarty meets your vehicle requirements while on the road with the RV, I believe it is the best option if you need/want a light tow vehicle. I would not consider driving my Smarty on long trips but as a runabout and toad - it is great. Fuel economy is well, OK, but I would expect something better from an 1800lb car. I get 38-41mpg but that is not why I bought it anyway and it does a fine job for my purpose.