Good morning. We are long time (12 year) smart car drivers. We have had three diesels and now down to an Electric Cabrio. The towing hooks are not meant for long term towing usage. I recommend not using them for towing behind an RV.
To install the tow bar go to a Mercedes Dealer (or smart car dealer if you are in the US). An RV shop can take hours to figure out how to get the body panels off. A Mercedes dealer (or smart car dealer in the US) has technicians trained on how to remove them. It will take a trained person 20 to 30 seconds per panel to remove them. For most of the panels it is that fast.
Good luck and happy camping.