In response to your first post - "...the cost to replace and reallyl maintain is not included in the standard cap rate discussion."
Before we go any further with your discussion we need to make sure we have the terms straight. When you say "rebuild the park" I assume you are talking the infrastructure not the homes (roads/water/sewer/pads/driveways/etc.). If so - then you can't factor in the cost of replacing worn out infrastructure into the cap rate because cap rate is specifically derived from NOI - which by definition does not include capital expenditures and cash set aside for replacement reserves.
But that's okay because you get to take depreciation on your cash flow of course - which reduces your tax bill - which in theory makes up for the fact that your infrastructure is always deteriorating - and so the gov't leaves you more cash to set aside as replacement reserves.
Cap rate is not to be confused with return on investment - it's simply a derived number used as a comparative yard stick when looking at relative pricing between two or more investments.
But you make a good point - high cap rate assets normally have high cap-x coming up so you have to factor that in, plus the cost of the headache factor - to see if your actual ROI really is higher form a high cap rate park.