OTOH, if it does involve upgrading things other than the tow bar, the towing package might be worth doing. For example, an oil cooler. Otherwise, the aftermarket tow bars are usually pretty good.

I think an eMTB is a good idea. You should be able to get one with rack and fender mounts, and you can always put slicks on it if you find yourself mostly riding on the road. My current plans involve converting an mtb frame to electric