I would try to find a mentor that you don't have to physically pay for first.

There is the pain of physically collecting but also it takes more effort for the bookkeeping than direct deposit. 

We can control it remotely and there's a physical key option for back up. 

Given that your 4plex MF property falls under this range, it aligns with the current zoning.However, to determine if you can build up to 9 units on the property, there are a few things to consider:Existing Structure & Occupancy: If you already have a 4plex on the property, then you'll need to see if there's sufficient land and infrastructure to accommodate an additional 5 units without violating other zoning requirements, such as setbacks, parking, and green space.Infrastructure and Utilities: Even if you can physically fit 9 units, you'll need to ensure that utilities (like water, sewage, and electricity) can handle the increased capacity.Other Restrictions: There might be other local regulations, covenants, or restrictions that could limit the number of units or the type of construction you can do.Parking & Accessibility: Increasing the number of units might also come with the requirement for additional parking or other accessibility features.Approval & Permits: Just because a property is zoned for a certain number of units doesn't mean you can automatically build up to that number.

If you have multiple SFR properties do you just have a single reserve fund and each month add a certain percentage of rents from all properties into it or do you try to keep separate virtual or physical accounts for each property?  

Don't get emotional on the physical presence, but do manage your expectations from the numbers.

One isn't better than the other, there are pros and cons to both.I like real estate because it's a physical asset and I like the market because of its' liquidity!

For the average landlord, make sure there is adequate cash flow to weather the storms -financial and physical.

I'm very hands on and would rather be able to physically see the property and keep an eye on things without relying on other people or taking time and money to fly out of state. 

California's own nexus rules regarding physical presence could easily be used against them in this case.