There is not just one kind of marketing, and any marketing that is isolated is bad marketing.

I love the neighborhood strips that are somewhat isolated or land locked where they just can't build more. 

As Joe mentioned...People need to stop isolating: markets, deals, location, one's specific circumstance or situation, wholesaling, Buy & Hold ,flipping, man, woman, "I am only 16 years old what should I do", 2022, 2045.. etc. etc."

Single family gives me isolation between properties, so if a problem occurs at one property, it doesn't affect all tenants.

So...Look at what you are doing my dude.You are cold calling, Driving for dollars, and whatever else you are doing that DOES NOT ISOLATE MOTIVATION, but then wonder in dispair why people ghost you?

Individual series are completely isolated from each other from liability standpoint.

====Right now (according to the seller), the gas lines to the range / stove  for 1st fl and 2nd fl are turned off because1. 1st fl stove/range needs to be replaced2. 2nd fl - There's a leak on fuel line somewhere between isolator valve in basement and 2nd range==== Why do I think there might be a major issue 1.

I know from experience they are better off living in isolated scenarios - single families - than in apartments surrounded by lots of people and noises.  

Should I solely rely on myself for all of this?

This affords the best isolation and asset protections ("Control everything, own nothing"), but still requires full insurance for maximum protection.One way of doing that is to have a revocable trust with you as the beneficiary.