Purchase price: $89,000 Cash invested: $23,000 Single family residence, 3 bed, 1 bath with a detached 1 car garage.

The one obstacle that you might be facing is the issue of self sustainability with a fourplex.

I've identified 4 Obstacles to creating wealth and have mentioned them before.1.procrastination2.spending habits3.inflation4.taxes All of these are removeable.

I have seen VERY few single family detached houses that would cashflow more than maybe $100 on a $200-400K investment.

I would buy an inexpensive detached single.

Price range in the area that I like for rentals in San Diego is $300-400k.What would be you'll advice on buying one a year with 25% down since I like buying detached 2 units to mitigate my risks?

Let consider the obstacles.1.

Attached or detached?

Where this is a local governance bylaw, you will find communities provide a variety of ways to regulate the size and occupancy of an accessory unit.Here a accessory apartment in the basement of a single family dwelling must conform the the following:(a) Where permitted, basement apartments shall: (i) not result in more than 2 dwelling units contained in any converted single detached dwelling; (ii) be secondary to the main dwelling unit, and not exceed 75 m2 or 75% of the floor area of the basement, whichever is less; (iii) contain a maximum of 2 bedrooms with the floor area of each bedroom not exceeding 15 m2 ; (iv) be completely self-contained; (v) require 1 on-site parking space, in addition to the normal requirements of the zone; (vi) not permit a group home, tourist home, home occupation, child care centre - small or child care centre - medium on the same lot. 

Makes me look into the future obstacles now and say "One day, these will all be laughably tiny in my rearview mirror."