Although it wasn't on OP's original list, I also highly recommend Brown Derby! It's not only my favorite restaurant in DHS, but at WDW! But if OP is on the dining plan, I can see how the 2 TS credits may be a problem. We like Brown Derby because the food is great (cobb salad,grapefruit cake, yummy drinks, nice kids' menu, outstanding appetizers) and we enjoy the theme/atmosphere. We are always comfortable with our three boys there (ages pre-school to pre-teen) and it's so conveniently located. It's not as pricey for us because we use our TIW card for the 20% discount, and because my husband is usually the only one who orders an entree. We're not big eaters, so we have a combination of kids' meals, entree sharing and appetizers as entrees. For lunch, we all get either appetizers as entrees and or kids' meals.
We've also been to Mama Melrose, 50's and Sci-Fi.
I like Mama Melrose - just standard Italian, and a good choice for dinner (too heavy for us for lunch.) But my husband hasn't been crazy about the food quality there lately so it's out of the rotation for a little while. The rest of us will be ready to return if it fits into the schedule in the future.
We love 50's and highly recommend it - last time, I had the wedge salad and shared the chicken pot pie and it was outstanding. I'm usually not into the "antics" that I heard about at 50's, but once there, it was really fun and we all enjoyed it.
We like Sci Fi for lunch, but not so much for dinner. We thought the burgers and other standards were good, but did not enjoy dinner entrees. I think the other issue that impacts our view of Sci Fi at dinner is the dining plan - we didn't find it worth a TS credit for dinner when we were on the dining plan. But with TIW, it's a good alternative to CS for lunch and fun to do every once in a while.
We've always thought about leaving the park for a meal, but we've never done it. Getting three kids in and out of the park just takes a lot of travel time for us. So even though we can get back and forth to the BC in about 20 minutes from the front gates, it's more like 30 minutes each way from somewhere inside the park. We stay at BC, and Beaches and Cream is great, but you can't get an ADR there, so if it's crowded when you arrive, that takes more time. On the other hand, if you are leaving DHS at the end of the day, don't plan to return to the park, and have park hoppers, an ADR at World Showcase in EPCOT would be a great alternative!
Good luck with your planning!