Now they're paying the price, plus double closing costs and taking on additional risk. 

It actually doesn't matter if you are purchasing for cash or financing - it matters how much the purchase + reno will cost compared to the after repair value.

Renovations are high cost items 

Do I need a *business* checking account to accept rent payments and pay for maintenance/repair costs as they arise?

Also, we plan to make the farmhouse and growing building/s nearly net zero, which will lower cost of utilities to zero.

I guess my questions are in how to calculate the cost of a rehab?

They might cut corners on essential structural or system repairs, leading to hidden issues that can be costly to fix later.2.

There are also additional costs of operating and maintaining an LLC, like separate bank accounts, annual report filings, tax filings, etc.2.

I received an estimate to make room for a hot tub that does NOT include the cost of a hot tub.

It will be self managed, I will be near the unit (less than 5 mins away) to clean and take care of any issues.My numbers:Approx Value of Home $240-280kCurrent monthly cost / $860 mo (mortg,ins,tax)Utilities / $250. mo (elec,gas,water,trash,internet)Cost to run as AirbnbApprox monthly cost with STR insurance ($250/mo?)