Went to the greater Mystic/New London area this weekend, and was absolutely steered right by Chowhound. Since the posts that got us into the right places are kinda old, I wanted to post a later-dated report as well.
1) Go Fish in Olde Mistick Village (near I-95 & CT Rte 27). You wouldn't think that a fish restaurant that isn't that close to the water and is in a touristy gimmicky shopping area would be good, but this one is. We were feeling a bit flat, so we got two of the lesser-priced things on the menu and were pleasantly surprised. Steamed salmon came with some nice veggies and a soy/sesame oil sauce, as well as some udon noodles in a peanutty sauce. The udon were overcooked, but the salmon and veggies were nice. Fish and chips were good, too. The hostess wasn't so friendly as she could have been, but our server was attentive and amiable.
2) Noah's in Stonington (breakfast). Wonderful. Nice fresh food, pancakes that didn't weigh a ton, good service, good coffee. I had the special omelette (crab, spinach, chèvre) and the SO had the raspberry pancakes. Both very good, though the omelette was a little overcooked.
3) Jasper White's Summer Shack at Mohegan Sun (early dinner). Adequate, especially considering the other options at a place like this. The cod cakes were not terribly zingy, but they were coddy. The shrimp roll (according to the SO) was underwhelming, but some decent flavor. We happened upon a good server who told me the iced tea machine(!) was broken, agreed to make me iced coffee, and came back with iced tea when it turned out the iced tea machine was fixed. Love it when people actually think. Big line when we left the joint around 5.30.
4) (not from Chowhound) Bartelby's Cofee in downtown Mystic (breakfast). Good coffee, nice sunny window seat. Muffin was a little dry and almost scone-like, though on the positive side that made for good dunking.
It's also worth mentioning that these places were not as crowded as they might have been, probably because it's the off-season for Mystic.