Hmm... It does make it harder to get a car back behind the post office without Chester st, but I think it would make it easier to get back there on foot. I've tried to make walkability a priority over drivability. Perhaps Bowers or Russell could be flipped to Southbound to compensate, or they could add a cut through through the Dover St lot?

A left from Highland to Dover would be allowed. Think of it like a normal 4-way where the 2 lanes of Dover/Day just have a really big median. From Day you could go left/straight/right, too. There might be room to squeeze in some waiting space so the left turn Highland->Dover doesn't block other westbound traffic.

I didn't know about the new grocery mart. Parking nearby is definitely important for that. There will be expanded parking at the end of Summer St 300ft away (comparable to the far side of the Star Market lot). With Chester now a dead end, there may be opportunity for parking there, if there's a reasonable way to turn around. I haven't been but I bet that in a location like this they're depending more on walking/biking than the average grocery store.

Thanks for your feedback. These are exactly the kinds of concerns I want to hear.