There are a lot of variables to be considered ...
Start with your capabilities
Can you change a tire?
Can you replace or service a wheel bearing?
Can you do minor
electrical or handyman repairs?
These things can frame your needs.
Next,What do you want?
Do you want collision and/or comprehensive?
Do you need only road service and towing?
Check with your car insurance carrier to see what is covered when towing and whether they offer supplementary coverage for the trailer and what kinds for how much.
There are also specialty companies for road service from AAA to AARP to Good Sam.
You might check if your car is under warranty...
My Ford warranty covers road service and towing for my car or my trailer or both.
My car insurance also covers towing for both.
I have separate Comp and collision for my trailer through through the same carrier.
If you are not too close to a large city you may also find that towing would be cheap enough for out of pocket payment.
The best insurance would be to learn a few road service skills so that you can take care of the minor stuff yourself.
Most of all learn how to stay safe and be aware of your surroundings in an emergency.
Remember....