They are also a convenient way to prove I am intelligent enough to learn new things like medical device regulations or commercial real estate sales practices. 

Lenders require a hold period due to underwriting requirements from regulators.

The CAM license would help you understand about property management, rules, regulations, statutes, etc. as that govern your state. 

You might want to look into regulations regarding renting per room (I think NYC considers that an SRO - single room occupancy - and the building might need to be zoned for that). 

However, design in such a way that they could be split per current setback regulations down the line (separate water & sewer & utilities too).

It's completely feasible to achieve enormous levels of success investing out of state - but keep in mind that when you get involved in a deal that is not local you're losing some control, and your visibility & oversight of the deal is dramatically diminished.Unless you're buying a turn key or getting into a PPM or some other commercial investment vehicle with a group that is managed and regulated, you may want to consider keeping it local until you've gained the experience and knowledge, and developed the out of state relationships necessary to be successful from a distance. 

I would hire a surveyor, this will prevent any problems down the road, then there is no question where your property is. also check with your town zoning ordinance on fences, you will have to get a permit, the height of the fence is usually regulated and the distance back from the property line you have to install it ( usually around 5" back) posts on your side and the fence facing the neighbors.

I'm hoping that some "big pocketed" Angelenos on this forum might know the answer ;)As an aside, while I'm of course grandfathered in the sense of not having to tear down my house, I'm relatively sure that you can not add any square footage or do major remodeling without adding a second spot, i.e. complying with current parking regulations.

I'm assuming a TOPA is similar to tenant estoppel, due to them not having a written lease they are month to month tenants and those regulations apply, so keep that in mind when doing your research on local laws

See https://noprop10.org/On AirBnB in San Francisco - The City of San Francisco has strict regulations on AirBnB in the city.