The main risks I would say to watch out for are any family dynamic issues that could arise as things like this could lead to issues that didn't exist previously.

The macroeconomics are on fire here - population growth, job growth, and companies moving and developing here.

Are their listings detailed with good quality photos?

It could be the first, the last, or any of them in between. 

They are a portfolio lender.   

Keep in mind this is a self-directed account and most are not.  

Any tips on sourcing land for mobile home parks?

Found T&H realty services to be pretty interesting as they provide both buyer brokerage service (to help me find deals) as well as do property management i.e. they are not full turnkey provider necessarily, but reduces some of the hassle for me I guess as an out of state investor. 

entirely stick frame and if stick frame are you using TJI joists, what kind of structural sheathing/fire rating requirements are necessary? 

There's a very good chance the issue(s) you face have already been discussed and answered.Ask questions in the appropriate forum.