I think the most significant factor is choice. 

For most of these types of loans, the equity position and your credit profile is the main deciding factor.  I

I have changed all of mine to electric. there's the initial cost of rewiring, but the hassle factor is well worth it.

And then the proposal is going to go into the sausage factory, and your "flat 15%" is going to come out the other end so garbled, unflat, and mangled, that I suspect the lesson learned will have been to focus on congressional and senatorial races if what we care about is some specific legislation. 

I have since forgotten most of the skills I had learnt (which was no where near the level that could help me get deals across the line) and recently (Jan 2019) I was trying to get to another success reflex so that I could kickstart my success.. but no response by him on WhatsApp or Facebook and the care factor I feel has gone because I am not a platinum member- but still $50k ($65k AUD all our savings) surely deserves some respect and a simple response to a message?

External obsolecence or aspects of less desirable elements are also considered such as being near a factory where noise or odors are present, high traffic areas or poor condition of surrounding properties are evaluated as well.

I don't visit a factory or an office of a stock I buy, so why should I visit a property I buy?

From Dave and Frank'/s boot camp the standard valuation formula based on NOI (as apposed to value Don used)(lots paying rent) x 12 x (rent (lot or home rent) x (expense factor see below) = NOI.expense factor if 100% lot rent is: 0.3 or 30%, expense factor is at minimum 0.5 for park owned homes.  

I might suggest traget direct mailing to homeowners that are adjacent/near to blue-collar and service type of job/employment centers (factories, light manufacturing, etc) where jobs are being more apt to be lost.

Of course a limiting factor is, not everyone has the expertise or track record to secure a construction loan from a bank for such projects.