Focus on getting that first investment property first and if you want to help chip in and pay off her debt, more power to you, but make yourself and your goals priority #1.

That will likely be higher due to needing to pave with aggregate to keep mud/dust down.On the power, it may be just as cost effective to connect to the grid and much more reliable for the tenants.

House hacking is just so powerful guys. 

Very powerful but there is much more to it.Different parts of the asset can be depreciated on different schedules.

How far will you have to drag power or how long till can get water there. 

Boston is a heavy appreciation market so focusing on that and debt paydown are the more powerful tools in this case, along with lowering your living costs.

I plan to pay cash for properties to get the best price I can, then do a cash out refi, and start the process again.If you buy it low enough you can get all, or more, of your money out with the refi.I have enough cash to buy two properties,  so I'm not without purchasing power for 6 months while I wait for the property to "season".

Now, if the landlord decides to use the power of the lease to evict the non-paying tenant, and the courts decide in his favor, the courts issue a writ in favor of the landlord. 

More than likely its appropriately powered, fully functional, and has proper efficiency.

Do developers inflate costs to maximize borrowing power or what am I missing??