If your husband is only buying beverages, there is a 7-11 on the corner of Katella and Harbor. They sell cases of water, lots of sodas, snacks, and also some sundry items. If he will be buying a lot of things, he could get a cab or you could go with him and split up the shopping bags.
The Target is about a mile south of the parks on Harbor. Don't know the exact ART route number, but it is the one for the Embassy Suites Garden Grove, the Sheraton Garden Grove, and the OC Hyatt, which are right across the street from Target.