one way to do research, no matter where you are in the US. is google earth the area, food, rental cars, stores, lodging all show up near to where you want to travel
There is an Avis car rental very close by, near the convention center. Address is 200 W Katella Ave, near the corner of Harbor and Katella. My husband used them back in August! He needed to pickup a rental car but return to a different location and they were the only car rental company who didn't charge more for that convenience.