Hands down other than major developers hedge funds and big time syndicators the biggest money in real estate today is the successful Guru trainer etc.. 

I can also see the ends of the Commuter Rail lines being good too...like Haverhill for instance  The Salem/Beverly area is great and pretty pro-development/housing from what I'm hearing.

I'm going to reiterate what's already been mentioned above, but I'm going to actually give you examples of why it's relevant to you to find a U.S. tax professional.1 - You're going to need to file U.S. taxes once you have property down here, there's federal filings, state filings, and sometimes local filings too2 - Tons of tax treaties between the U.S. and Canada that are easy to miss and can cost you a lot of money (important one with rentals - effectively connected income - if the professional you talk to doesn't know what this is, run away)3 - The amount of days you spend in the U.S. needs to be tracked and if you go over a threshold, all of your worldwide income could be taxable by the U.S.4 - Selling real property means up to 15% of your sales proceeds might not be available to you for years (FIRPTA)5 - Lots of nuance at the state and local levels, which both want to take as much money from you as possibleMain takeaway here is that you should find a U.S. based tax person.

I'm trying to understand how they collect data so as to develop the best comping practices.

Sales is a time-intensive venture, and it takes years to develop a pipeline of clients.

Is there a local developer/builder who might be interested in the whole package?

I have checked with our lender and keeping this home's mortgage will not effect qualifying for our next house.4.

If this is your 5th deal you should have already developed a banking relationship with a commercial banker.

The macroeconomics are on fire here - population growth, job growth, and companies moving and developing here.

As the new owner, you’ll want the lease and your landlord insurance policy to take effect as soon as you take title to the property.Temporary Lease Considerations:While short-term leases can work well, leasing to a seller long-term often leads to complications.