I would assemble your case.

I know that's a vague question because I do have an idea (assembling a team, direct mail marketing, etc.) but still it's very theoretical.

I was going to suggest the same thing as Chris.We've done that on what I imagine is a much smaller scale than what Chris has probably done, but it's worked well, and has the extra advantage that the crew is accustomed to working together, so there's a lot less stepping on toes than you get with a new crew that you assemble yourself.

Until just a couple of weeks ago, ADU's were not permitted on multifamily properties in Oakland however, a series of state assembly and senate bills were signed into law that requires local governments to permit such development, regardless of your zoning density limitations.

To accomplish this, I am going to work to develop a pipeline of leads from various sources, assemble of team of real estate professionals I can contact and contract with, and by continuing my education wherever and whenever possible.My First DealI am using the term “deal” loosely.

Tasks include replacing smoke alarms, window screens, mounting TVs, assembling furniture... light carpentry and/or painting skills are a plus.

I called Virginia Homes Building Systems and they quoted me about 165 including shipping for a factory-built, assemble on your lot triplex about as you describe. 

You can install either multiple smaller systems or a larger, multi-headed (multi-zoned) system.Regardless of the heating or cooling system you install, your biggest bang-4-buck will come from air-sealing and improving the building envelope ... this can be a simple as replacing weather stripping on doors and windows and caulking trim to adding additional insulation to the exterior (or interior) of the wall assemblies / attic space and replacing windows and doors.You should probably start with having an energy model {aka heat loss analysis} performed on your house which will identify the current energy losses and the measures you can take to improve the performance.

Here are my experiences with RTA for both flips and rentalsPositives-They are all plywood boxes- no swellingThey can be shipped anywhere-fastYou can either have them shipped flat boxed or prebuiltIf you build- screw and glue for durabilityThey are a lot easier to assemble than IKEA            (not a box in a box, Not a thousand pieces and no Schmoo directions)quick turnaround once orderedSoft close drawers and doorsThe quality is high enough for 750k homes (in Denver). 

Once you've assembled one you've basically got the concept down for the rest.