After searching for Hound recommendations for this area and finding very little, we have just finished up about 4 days in Anza Borrego and can report that there is decent, even quite good food to be found there.
We were staying at the Borrego Springs Resort, which is a perfectly fine place for families. The restaurant serves a decent (no buffet) breakfast -- pretty standard hotel fare -- a spot or two above mediocre. We ate there twice -- the oatmeal is "fine," the egg dishes above average (cooked to order the way you ask for them), the juices come from the finest of Tropicana cartons, and the coffee is weak. Fruit plate was large and pretty good. Everyone is very nice. We did not try it for dinner -- the atmosphere was too red velvet and octogenarian for our tastes (every single dinner patron was at least 80 when I popped my head in) and the menu prices typically hotel high.
We had lunch at Calico's, a little sandwich and pizza shop in The Mall. This place makes exellent pastries -- we went back twice for blueberry and cherry turnovers. The kids had chicken soup which was definitely homemade and pretty good, and I had an egg salad sandwich. I found the bread not soft enough, but otherwise the place is a nice little place to grab a quick lunch.
We had one dinner at Jilberto's, the taco place on the main drag. It's a humble little shop -- give your order at the counter and then go pick it up; if you want beer with your food, you hit the liquor store next door and the staff at Jilberto's will pour it into styrofoam cups for you. I wasn't enthralled (the "fish" tacos had breaded and fried fish in them!) but the food is edible and there's a huge amount of choices. My beef tostada was a bit greasy, but I liked my cheese enchilada. Beans and rice were so -so.
A lot of disappointment that "the French Place" -- I think it's called The French Corner -- was closed until April 9th, but it looks very promising.
The two best places that we ate at, and we found them to be really very good, were The Red Ocotillo and the Krazy Koyote Cafe, both of which are on the property of the Indian Palms, a very retro hotel off the 22, a couple minutes off the main drag. We had breakfast and lunch at the Red Ocotillo and dinner once at the Krazy Koyote. Food is very fresh and prepared to order, so it doesn't come racing out of the kitchen 5 minutes after you order it. Blueberry pancakes, french toast, tofu scramble, bacon, all excellent. They serve breakfast all day.
For lunch one day, we had the California Club, which was a bit piled on with the meat, but otherwise good. A very tasty Caesar salad, and my kids split a burger, which they felt was among the best they've had (they are little burger afficianados, their favorite being from The Rusty Pig in Oceano).
Dinner one evening at the Krazy Koyote was very good. Staff there was very friendly. We had the baked brie appetizer, one daughter had tuna sashimi, the other had 4 cheese penne (you can order off the Red Ocotillo menu for dinner at the Krazy Koyote) and I had a wonderful shrimp scampi served with brussel sprouts and very good mashed potatoes. Perhaps the best thing about the place was the Toasted Coconut Snowball I had for dessert -- this was a relic from my Pennsylvania youth and I hadn't seen one on a menu in decades. It needed more coconut, but was otherwise a tasty trip down memory lane.
I would probably avoid Carlees -- it's your typical small California town tavern restaurant with enormous portions of vaguely edible food. We had ribs, steak and pasta, and nobody could, or was inclined to, finish their meals. My massive rib eye was mostly fat. Although I will say, for $8, they give you one hefty shot of Patron. STars for that.