Do you think this could be corrected with how many 4plexes are probably financed with ultra low 30yr mortgages?

It looks like there are about 1,200 listings in the "Village of Four Seasons" section near the Bagnell Dam.The entire area rates really low for seasonality, so you may consider how much a week in the summer will actually cost you if that's your "break-even" time.Happy to give you more data if you're eyeing a specific property or ZIP code.

They’ve secured low rates and rapid equity increases due to the last few years of Fed/gov intervention.   

Huge tech grow, low taxes, and landlord friendly. 

Consider factors such as location, amenities, and market demand.Run the Numbers: Calculate your potential cash flow by subtracting your mortgage payment, property taxes, insurance, and maintenance expenses from the expected rental income.

Are people still investing is San Diego or have the high interest rates and low cash flow moved investors to other markets?

@Dwayne Clarke going to take an educated guess that what you were cautioned about is buying someone else's problem.Over the last couple of years, many OOS investors bought a bunch of SFR and MFR properties with LITTLE due diligence.Many were sold Class C & D properties that they thought, or expected to perform like, were Class A or B.Once they figured out what the properties really were - via tenant nonperformance and never-ending maintenance issues, they looked to sell them.If you know what you are doing, their loss can be your gain.If you are new and do NOT know what you are doing, then you'll just be the next "sucker" that gets taken.

Many thanks to @Jake Baker, @Chris Seveney, and @Bonnie Low.

More specifically, my questions would be:What type of account(s) do I put the money I save for maintenance, vacancy, capital expenditures, etc. into?

jump to the top of the list.Anyway, it's still lucky that it's a pretty cheap educational experience -- taxes are low, keeping the lot mowed doesn't cost much.