The best way to tour the US is to rent your own car or caravan. On both occasions we were there, we rented our cars which gave us the opportunities to see the beautiful parts of the US West Coast which includes LA, San Francisco, Las Vegas, San Diego and also Grand Canyon.
As we are travelling with 2 kids this time, PiggyBeng decided to pay for additional insurance as well. With that we are insured should there any break downs along the way since we are driving long distance on most occasions. At that time we are not aware of any car repairing workshops since we are not locals. It will be extremely troublesome too if our car break down especially when we are in secluded areas.
So, it will be good that you find out about services available such as those offered by some major auto repair sites when planning for your trips. You should check out Repairpal.com as they offered comprehensive services.