The best way to find the next good market is to find the hot ones near you and go two towns out in each direction and see which one is progressing more.

Real estate is capital intensive. 

When you are investor friendly it means you understand the metrics of the buyers property search.I have seen so many agents get comfortable and simply add their new buyers to the "Hot Sheet" and they blast the buyers with properties that do not even fit the buyers cash flow needs or budget.

Your architect can create this for you.For hot water heaters, is there a lock on the door to that room?

Right now, this is working, but we're in a hot market.

Can't include furnace, hot water tank, central ac and some other built-in appliances - check your local ordinances.

FB marketplace, join all the real estate FB groups for your area, REIA meetings, real estate meetups, talk to agents, get on Zillow and look for properties that look rehabbed/flipped and find out who sold it (the seller will be the investor you're looking for) and ask them if they want another hot deal in the same area.

Does anyone know of any hot markets in Macomb County, Michigan right now?

If we find Lithium somewhere, that may also be a hot topic like it is in SW Arkansas right now.   

Hot water heater, furnace, gas, electrical box, HVAC, oil tank, plumbing pipes.