There is no one-size-fits all rule about best investments.If you know rentals, flipping, or lending, then focus on that area you know best.There are considerations about keeping things at arm's length, choosing investments that are passive vs active in nature, and some tax complexity around the use of leverage that require some guidance from a professional but can still be very profitable.  

Are there any Milwaukee investors that only focus  on cash flow or is the natural progression to seek appreciation after reaching your cash flow number?

However, there is a case for RV parks that more closely mimics a MH park when the location is appropriate for a full time living solution.The nature of RV parks can also vary across a wide spectrum.

Naturally my sights go to wholesaling, as the prerequisites are attainable within my allotted window.

Is this a natural progression in the business, or something that should be kept separated?

You also need to be aware that custodians are passive in nature and simply process transactions at your direction.

I am analytical by nature and have bouts of anxiety. 

Factors involving mother nature I stay away from..

Natural rent increases due to limited housing supply and increasing demand, appreciation, principle pay down, and depreciation tax benefits all contribute to fantastic overall returns in this market even if initial cash flow as a percentage of purchase price is not as attractive as other markets.

I bought Nature's Miracle Oxy formula for cats.