What is the most efficient way to do this?

Another issue I am finding is there is a negative correlation with the size of an applaincr and the price of the item, these efficiency appliances cost more than standard appliances.

They claimed that MLS deals were not that efficient way to get a deal. they suggested going to local banks for REO's and wholesaling.

I'm just giving every realtor I talk to my criteria and telling them to send me what they find so I can analyze myself but it sure would be a lot more time efficient and more effective if I can find an agent who understands investing and/or invests themselves.Anyone here on BP want to connect?

Using half a duplex as a vacation home is not profit optimizing, is not tax-efficient, and gives you less flexibility for your vacation plans.

Off-site built structures will be an important part of that as they are more efficient to build and thus more affordable. 

Additional upside can be found in the areas you mentioned - ease of access, economy of scale with service providers, time efficiency for management, possibly offering additional price points in your portfolio, ...Contiguous property is worth more to adjacent owners.

I think you will see heat-pump driven dryers become more common as they are so much more energy efficient themselves and you do not have to cut a 12.6 sq inch hole through your building envelope for a vent (another inefficiency)We just replaced an{other} {only} five year old Maytag (made by Samsung) 24" laundry set (vented dryer) for which we could no longer obtain parts with a new Bosch pair this afternoon.  

This is probably the most efficient and profitable route to you. 

Hire a payroll company to set you up - they are cheap and efficient.