So far I have advertised on: zillow, trulia, fsbo.com, craigslist, 10 FB groups, FB marketplace, letgo, offerup, bandit, signs, and flyers to nearby apartments and businesses.

i think i saw that one advertised online. how did it go?

@Kyle Gnerre "I found a guy on craigslist" is all you need to know that it's not legit.What millionaire real estate investor/lender, is going to advertise that they have millions of dollars on craigslist.Would you do that?

Advertise it as "Investment Property with Renter in Place"I can't imagine that the value of the property will change much in a correction.

@Donald Powell, what you are talking about is brokering real estate, which is illegal to do without a real estate license in all 50 states.You're not advertising a contract, you are actively looking for a property for a "client" which is 100% brokering real estate. 

A few ideas, all of which require research and feasibility assessment as they depend on local regulations and/or affordability / demand in your market:1) add additional lots by developing unutilized land2) add storage space / shed for residents to rent for a monthly fee3) offer a cable or bundled cable / phone / technology package to residents; buy services at wholesale rates and sell to residents at discounted retail rates4) adjust rents based on size / location / views/ambience of lots in the park5) bill back water/sewer/trash, where applicable 6) offer billboard/advertising space if your park has decent traffic visibility7) lease space on property for cell tower operator 8) cut grass on residents’ lots for a fee9) paint/wash/skirt homes of residents for a fee10) fill vacant lots / vacant land with area for long-term parking for boat/RV/equipment 

Many areas will have special regulations around unrelated adults living together (aka student housing) so you should research your local regs to see what you need to comply with from a code standpoint.Also yes, make sure you understand federal fair housing laws and don't break any of those in your advertising or leasing.

Advertising, software, travel, etc. while the only income I foresee is acquisition/AM/exit fees.

There are a lot of expenses such as fees, dues, advertising, gas to drive around etc.

In fact, the opposite could be true.  506(c) allows firms to advertise their offerings.