I researched this a bit after having the thought the other day as I started planning to sell my portfolio slowly over time.

Remodeling now and then selling Lessons learned?

So getting ownership over something in that context makes a great deal of sense, as long as the longer-term plan is to move out and rent out the property, rather than selling. 

Offered to buy if he ever thought of selling.

our first exit strategy was to sell own a wrap around mortgage creating a second note and financing our desired equity position but to find the end buyer was a challenge so we decided to rent it out after 3 months of vacancy Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I'd focus on 150,000 sq ft and up deals so you get the densities you need. we just proposed 84 units on a lot that is 4500 square feet in Columbus Ohio with reduction in parking from 111 cars to 0 and we will lease off site parking. shift parking off site to save money on garages or push it into public garages. if the numbers work build structured parking which most the time they do it just depends on the deal size. if you want to sell to institutional investors you need at least 100 units in my opinion but the sweet spot is like 150+. in downtown columbus our market you can get about downtown unlimited height land for 1.5 million an acre.

That is why I would stay away from a condo.I know someone that just had to sell their condo because the ever increasing HOA fees made it unprofitable on a property they had owns for years.

Any recommendations in Boston area for flip?

Local banks who don't re-sell these are typically your best bet, they like relationships.  

I'd like to sell one of my rentals and put the proceeds into stocks instead, but if the tax hit is too high, I'd do a 1031 exchange.