I am looking at single family homes that need reno in the 100-150 range.

.-  For a loan, keep in mind that banks are in the 4-6% interest rate range these days for investment properties, so a lender will be higher than that. 

Value is ~$1MM, putting your loan amt in the $600-$750k range, too small for Fannie/Freddie small balance. 

I am thinking I could find a new rental under the $250K range in the Boston or Providence Metropolitan areas right now (as long as the deal is right of course).

Having lived in Boulder, I can tell you that superior weather and outdoor opportunities are a big draw for that age range.  

In my town a $300 difference would be enough to turn off higher price range applicants.

It isn't a free service, from what I've seen, I believe the costs range from $100-200 per cert. per animal.You are allowed to ask for official documentation from the medical/mental professional who provided the ESA/ADA certification to verify the legitimacy of the animal.

You can choose what market to target, the O2/ E6 range or the O5/ E9 range.

You can also change the date range to display what has sold in the last 90 days, 6 months, 1 year, etc.

I think you might have some difficulty finding a duplex in your price range but you never know.