Can anyone provide insight on the average cost of insurance for Airbnbs with pools in the Boston area?

I think your best approach is to pretend you are the investor yourself, calculate build cost (mortgage with interest) + Maint / cap expenses/ management fees according to your zoning and then compare that to the average rent in that neighborhood.

For example, bank accounts we control and specific investor capital accounts are all tracked in this same software.For our investor reports, each month we download spreadsheets, write a narrative for the month's performance and then export it all to a PDF.

But it is not an easy home to fill given the rental rate is above average for the neighborhood (but well below average on a $ per sq ft basis). 

Are there any good resources online to be able to get an idea of average monthly/yearly expenses like utilities, etc. for a given zip or city?

From what I’ve read in the Wall Street Journal, average rents in Providence are up about 15% over the last two years, which could work in your favor.

Just calculate the average price/sqft and use this, but this isn't good because some out of date also get sold, and the likesFinally, how closely do investors follow the 70% rule?

Conversely keep in mind the prevailing "average" for Property Management fee is 7%+.

Percentage is a rule of thumb, so whether you get a 100 a month or 1000 a month, your maintenance is going to average around a fixed number not a percentage of your rent.

Flipping is probably a little more intense, but can still be done with a day job, but again, my average flip versus my average rental: flip has made much better returns.And as for generational wealth and handing down something to your kids... well, I guess I view it as: if I can hand my kids a $10mm trust fund held in public securities, or $10mm real estate portfolio, they are going to be pretty set either way, but a real estate portfolio will continually have costs and work, a brokerage account is a bit more set and forget, with some periodic rebalancing.