Are flat-fee MLS sites or otherwise free listing sites like Craigslist the only options?

Aside from Bizbuysell, loopnet, crexi, and Horse & Hearth, what other listing sites have campgrounds and resorts for sale on them?

It's a bit old school but the price is reasonable. there're better systems out there but you pay for the premium. 

Some of the usual reasons why people would sell to these companies: If there is money owed on the house, the house is in terrible shape, you don't feel like dealing with selling it, or you don't want to pay realtor commissions.

I've been going through "The Multifamily Millionaire:  Volume 2" and in Chapter 13, they talk about property management ranging from 4-6%, on top of on site management that is on the owner's payroll, separate from property management, and that you should budget about 1 staff member for every 40 units.If you (the owner) are already paying a property management firm, why do you have to have on-site management separate from the PM? 

Instead of resolving the issue, he’s threatening to place a lien on my property unless I pay him.I want to understand how does this lien work and this one example, I have such few examples with handyman, plumbers etc  they always keep threatening if you don't pay us we will put lien on your property. 

Some sites will just send something like no information available.    

Additionally, as reflected on your Appfolio Owners Statement, the tenant attempted to pay rent, albeit all 3 times it was returned as NSF. 

Debt is not a bad thing, and you can always use the additional cash flow from a property to pay it down quickly if that is part of your goal. 

What documentation do you ask for as proof they can pay?