Dining near the Gorge Ampitheater?
Hands down you must try Tendril's: restaurant and the Cave B Inn, at Sagecliffe. The web site is here: http://www.sagecliffe.com/Tendrils.htm
We were there last month and the menu is great! Focused on local, seasonal, fresh foods with great presentation and we loved everything we tried. The best part is that this is an estate winery and the bottle prices in the restaurant are not marked up from the tasting room! Their wines are fantastic and there is something for every taste.
This property is adjacent to the amphitheatre property, you can walk there from the camp ground! They also have a full service spa, beautiful rooms, and serve meals all day. One night we just had small plates in the bar and were very satisfied with that.
Chef Divina told me that he was leaving to open his own place in Oregon, but I am sure the place is still really great, after all it's only been a month.
Last time through the area I stopped at a Mexican grocery in Quincy, and got some good flour tortillas. They also had various Mexican takeout items such as carnitas and biria (beef stew) (though I didn't try them). Since it's an agricultural area, there probably are other decent Mexican options, including a taco truck or two.
There didn't seem to be much in George, except maybe a bar/grill or two.