That is the most common piece of advice I have received.  

E.g. fire rated construction requirements on main homes, survey & soils reports, utility upgrades. 

You will need to utilize a fix to rent loan, then after the rehab is complete refinance into a DSCR loan.

I take it that 35% is the common expense ratio for mobile homes?

I still have to see what's happening with utilities, but right now it would cashflow anywhere from $150-$300 (depending on the loan type and DP we select) with a CoC ROI between 9.9%-10.8% (lower than some other options we're looking at, but it already has tenants...)Thoughts?

https://www.biggerpockets.com/...12 Frequently Asked Questions (And Answers) About DSCR Loanshttps://www.biggerpockets.com/...8 More Commonly Asked Questions and Answers to DSCR Loanshttps://www.biggerpockets.com/blog/eight-questions-and-answe...What Documents Do You Need for a DSCR Loan?

Kids are adventuring and walking too and from school unattended, people park where they need to, people use common sense to make decisions more than relying solely on the rules, etc. 

This is a common tactic.

One of the most common derogatories are medical expenses.

I realize you are an expert on 1031 but perhaps "interest tracing" concept is less common...