My gut says to wait and hold our cash because by my (back of the napkin) math, it would take 8-10 months (being fully rented at the rates above) to make our investment back, and it seems likely that it will be much harder to rent units during times like this.

I’ve seen in some mobile home deal analysis that seems to be the off the napkin approach to MHP analysis. 

The law can be very strict on such things as security deposits and sanitary codes.

You must maintain your apartment in a clean and sanitary condition including prompt removal of trash and garbage and placing it in a collection point container.

Reading, videos, podcasts and scribbling on the back of napkins over the past few months has been enlightening.

I was recently purusing Zillow out of curiosity and was "practicing" running the numbers, back of the napkin style, on <200k SFR . 

. :)I don't have a calculator but here's my napkin math:ARV x 80% - Rehab Costs - Holding Costs- Closing Costs = Max Allowable OfferRents x 50% must be greater than mortgage payment (P&I).

Cap Rate is an easy "back of the napkin" metric to analyze the deal.

Back of Napkin calculations: Triplex: 3 bed, 2.5 bath Triplex w/garage ~ $628k total cost to build ($143 cost to build sq/ft). 

To your point, back of the napkin $150/nite x 180 nites = $27K Gross - there is no way it will cash flow.