I'm looking for a good town to stay in for a quick two day trip to CT in late July. Don't want to spend a fortune and I will have a car but would like to be somewhat close to the water and stuff to do.

Which town is best as a home base? Stamford? Norwalk? Mystic?

Danbury is close to Candlewood Lake.

Certainly not Stamford or Norwalk. Go East, young man (or woman) and grow cooler with the country! Mystic is much better, and the far better beaches of RI (surf) are within easy driving distance.

I am not sure what kind of "stuff to do" interests you but agree that Mystic Seaport is very interesting. The southern end of the CT River is also a good area to explore.

Not Norwalk or Stamford that's not at all what you're after.

If you decide on the Stonington/Mystic area, for less expensive lodging, check Groton. Also in Groton is the Submarine museum - run by the park service and free, including a walk through the Nautalis, first nuclear sub. Mystic Seaport and the Aquarium are both worth a visit, but not really inexpensive. In addition to all the ships, buildings, etc. right now the Seaport is finishing its restoration of the Mayflower II, before it goes back to Plymouth for the celebration of the 400th anniversary of the Pilgrim landing in 2020.

For water activities, there are kayak and stand up paddle board rentals in Mystic as well as sail boat. water taxi, etc.

Head about 15 miles east to Misquamicut State Beach if you want to swim, or to Watch Hill, for a more upscale sea side experience.

Many interesting well preserved 18th and 19th century homes in Stonington Burrough, farmer's market on Saturday mornings

I live in Stamford and can't imagine what you could find here (or nearby) to spend two days doing as a visitor (other than going into NYC). I think emalloy makes great suggestions which will provide nice variety of things to do and see, plus proximity to Rhode Island beaches.