You cannot simply use a mathematical formula as while one is simple, they will have to work with the engineers (civil, MEP) to coordinate exterior, entrances, grades etc.

Mathematically speaking, bay area market is extremely niche market.

With that objective you can mathematically work your way back to what you consider a "reasonable offer"  i.e. how much Net income (Rent minus expenses) will the property produce versus how much cash you put in to the deal.  

Is this worth pursuing further, on paper- it does make mathematical sense.

It’s a mathematical formula based on number of people, square footage, etc.

Not arguing existence of climate change, that's a mathematical fact.

This could mean investing in property flips or purchasing out-of-state rentals for more stable income, but it would require letting go of the $1,350 rental income from the manufactured home.What factors should I consider for each option, and how would an experienced investor assess this situation mathematically?

NONE of these "ands" is a guarantee so it mathematically is incorrect to call it a numbers game.it is NOT a numbers game.The harsh reality of the matter is you need to think, and stop accepting opinions from others just because you want them to be true.

I had previously listed it with another realtor and did not have any of the mathematical details in the listing.

So, here is the story: I read a book called Timing the Real Estate Market and the author gives a mathematical approach to timing the market that uses 5 metrics and moving twelve month averages to keep track of what the trends are.