This is a great conversation here - this is part of why I love the BP community and forums :)
If you're looking for a true BRRRR in this market, you're going to have to source off-market properties. That's just the reality in a market where home prices continue to soar and "highest and best" is being used on virtually all listings.
With that being said, there are still incredibly strong investment opportunities in many of the towns you mentioned:
-Glastonbury, Avon, Farmington: I'm a Glastonbury resident and appreciation is the name of the game. If you're willing to buy, hold, and benefit from long-term appreciation (5-7+ years), you'll reap the financial rewards. For example, the SFH I bought in 2015 is now worth 38% more! That's with me making virtually no material improvements to the property. Other home owners in town are experiencing similar equity growth.
-Manchester & Bristol: both of these towns are more affordable than the 3 mentioned above and they have strong rental outcomes. There are more multi-family and condos in these towns, which means you have a stronger likelihood of purchasing something as a rental that meets the 1% rule. You'll still experience appreciation in these towns, but at a slower rate. As such, it's important to prioritize cash flow in these towns. As a matter of fact, I am in the middle of helping a client secure a condo in Bristol that would meet the 1% rule.
-New London: lots of folks are saying that New London is on a similar trajectory as New Britain a few years back. Home prices are still reasonable, there are lots of multi-families, and cash flow is key. Only time will tell if the New London area experiences the same boom as New Britain has in the last 3-5 years, but given its proximity to the ocean, proximity to a few colleges, its affordability, and its makeup as an old mill/manufacturing town, I think it's a strong place to invest. I have a couple of excellent contacts in the area - a wholesaler and an agent/investor - who I trust and who have had a lot of success there.