A Garmin RV GPS is very helpful when towing. It helps keep you in the needed lanes giving lots of good notice, and advises against certain routes based on how suitable they are for towing. This took a a lot of stress out of going to Anaheim Disneyland.
Google maps is more useful for traffic tie-ups and construction.
Edit: I see it is on sale now, not a bad price:
https://www.garmin.com/en-US/p/660527/pn/010-02227-00