Hey @Frank Luongo ,
That is extremely impressive how much research you have done into each of these towns. I would like to point out that there are a lot of good indicators you are using but vacancy rate may not only deal with the city but also the home ownerships in the area. I know people who get very little vacancy because they go the extra mile to make tenants happy. As far as numbers for average cap rates, I couldn't help you on finding that but I would suggest that you find a number that you are happy with. You may be surprised and find an amazing deal in a nicer town if you keep all your options open that has similar if not better CAP rate.
I personally look for something that will make $1000+ month positive cash flow and a Cash ROI of 15%+ . I usually do my numbers around a 10% vacancy rate but honestly, I generally take out 2 months rent out of 1 unit a year as a average worse case scenario. I figure that if you lose a tenant and then go in clean it up and then take your time finding a quality tenant you are out 2 months at least.
Everybody has their own system of what they find works for meeting their needs, but I love going for higher Cash ROI. I don't take into account how much of the mortgage is paid off or the tax right offs that come with owning the house because I plan on owning the homes forever. So equity really doesn't mean much to me unless I plan on refinancing it our leveraging it for another purchase.
Good luck in your search. I believe Connecticut is an amazing place to invest even though we are a tenant friendly state.