On 63031 (Florissant), my properties are just slightly South of Florissant in Berkeley. My property manager suggested I buy my next properties in Florissant. I agree with the opinions that you (or your trusted advisor) need to do due diligence on the property and surroundings. But I disagree with avoiding North STL. If your on a limited budget like I am, you can squeeze more ROI out of lower priced areas. As an out of area investor, we need professional property management anyway. They screen and deal with difficult tenants, maintenance, etc. which is well worth 10% of rents, and offset by higher ROI. If you are going to try to manage the properties yourself, or have more money, or find a slam' hot deal, then yes, go for a higher class areas with lower returns but fewer headaches.
As for SFHs vs. MF, I own a Triplex in San Diego where land is expensive and deals are very competitive. In STL I'm buying SFHs wholesale at deep discounts with value add in repairs. I think deep discounts on plexes are much harder to find. My two SFHs cost $60k total, gross $1,300 rent per month and net ~$700. ARV is about $100k if I choose to cash out refi.
