Honestly, in the research I did, there are not many saltwater charter guides out there. Seems like most of the saltwater fishing is on larger party boats and the guided smaller charters are mostly aimed towards freshwater. We ended up chartering a half day with a guide out of Bass Harbor. We went with Bass Harbor Island Cruises and chartered their boat the "Fifinella" with Sarge as our guide. 1/2 day was $600. He took us south out into the Cranberry Islands south of Mount Desert Island. We had 3 adults and 3 teen boys and there was room for all of us on the boat, but really only room for 4 to easily fish at any given time. We were mostly jigging using cut mackerel. We caught quite a few cod, a couple of Acadian Redfish, and a few other random things that I have forgotten. There was a moratorium on keeping cod this year, but it sounds like the numbers are coming back and they are hopeful that there will be some recreation catch allowed to be kept next year. It was a good trip, lots of beautiful scenery, but if you are looking for world class gamefishing, the nearshore waters are probably not going to be much fun for you. If you just want a peaceful day on the water to let some kids catch some fish, it is a good time.
As for places to stay, there are tons of VRBO/AirBnBs up there. Unless you just really want to be in town at a hotel, for a small family (or even a large one), there lots of great deals that will get you a house or a cottage in the woods and many will be right on the water.