For me it very convenient to just log in to the owner portal and have the ability review cashflow/p&l statements, download expense reports for each property, pull lease agreements, make owner contributions for repairs if necessary, etc. so when I am dealing with my banker in getting a new loan for a property, I can provide him the financial info on my rental portfolio quickly.

If they did, I'm willing to take that risk because I'm confident in my ability to argue my position, my local judge is pretty fair and reasonable, and I can eat the cost if I lose.Your mileage may vary.

How do you know when you can trust someone so much that you just allow them to send you a bill?

As with 1031's they offer pros and cons. i agree with @Alina Trigub the first step is to define your main goal - asset protection, growth, tax shelter, all the above.

Appreciation exceeding rent growth as you mentioned.7% ROE is my bar for the risk and effort involved is all. 

Now, a great way to mitigate that to the best of your ABILITY is through fantastic tenant screening strategies and calling every reference provided to you by the tenants and sometimes do some extra outreach if you think you need to.

It also seems like it has the ability to grow due to its affordability and proximity to Santa Barbara.

My primary residence has 200k+ of equity(due to significant rehab and market growth).

(job growth, population, median home price, median income, house vacancy rates, etc)What are similar parks in that market lot rents currently?

This includes employment, population growth/decline and other indicators that you'll see on the census report.