Ugh, I hate scolding others while making mistakes. 

Eliminate debt, establish a budget, and save.

(Mistake #1, not checkin on things).

What was the biggest mistake you made when you began investing in real estate?

The financial benefit of reducing or eliminating income taxes very much out weighs the hassle and costs of a potential audit.You don't need anything fancy for a time log. 

My contractor eliminated a window in the kitchen and pulled some vinyl siding from the garage to replace. 

You also should have better screened the PMC before hiring them - a common mistake!

In my opinion, it's better to make mistakes starting out on duplexes and 4 units than buying a 20-unit after saving up a bunch of money and making a lot of mistakes because you have no operational experience since it's your first one. 

In the end the questions were geared towards encouraging me to:  1. eliminate my separate cleaning fee and include it in the nightly price, or 2. lower my cleaning fee to get more bookings. 

If the mobile has had elimination of title and is attached to the land, that is one thing.