My wife and I own a fully renovated 3/2 double wide on .25 acre  very close to a waterway .

Dave,Just an Insurance note, the coverage and pricing on Apartment Buildings can vary widely and I would recommend talking to your agent. 

I am removing the staircase in the building that goes up and down, I am instead cutting a 36 inch wide door in the foundation wall and pouring concrete steps on the outside of the building so the basement suite will have its own separate entrance.

It normally goes with a wide price offer, then they counter and your adjust accordingly to close the gap, or tell them it's to far apart, and we can't make a deal at that price, but your offer stands if they change their mind anytime in the future.

@Christopher RobertsCommercial rates and terms vary widely.

Multiple living areas (such as an upstairs living room as well as a downstairs living area). enough parking (focus on 3 wide garages, corner lots, or houses with long road frontage so as to not peeve your neighbors with cars parked in front of their houses).

One of the issues here is insurance, and that can vary widely depending on property age with the best rates, of course, going to properties built after 2001. 

Especially when there are already leases out there that are attorney-approved and widely in use. 

They sit on a 6 acre property and it has a 6 ft high 80 ft wide waterfall in the backyard.

This helps for building wide announcements etc.