I'd go with LL Bean Duck boots for midcoast - you're actually going to be dealing with a lot more months of slush and half-frozen mud than actual snow. If you're planning on heading inland frequently in the winter, get a pair of Sorrels for the cold, dry snow.

For gloves... I like Astrid for a huge pair of mittens to walk around in when it's really cold. But they're not waterproof. For waterproof maybe get something from a ski/snowboard store. (I happen to have Burton, but really anything marketed for skiing/snowboarding should be fine.)

Also you didn't ask about coats, but I like Canada Goose.

This.

In addition: "there is no bad weather; only inappropriate clothing."

Budget some money for warm coats, boots, socks, etc. The cheap stuff that looks the same... is not the same.

This also goes for indoor things like blankets, curtains, and slippers.