Now that you've got the debbie downer insight, here's my two cents
It's definitely an opportunity. IMHO the price per lot is reasonable. Owner financing may not leave you as much negotiating room on price but it's always worth trying, just make sure the numbers work for your endgame of not owning the homes.
For the homes you have a couple of options. First of all you can sell them in their current condition but maybe not for $5k, people will fix them up themselves to get a deal. I would run some test listings on Facebook Marketplace and see what kind of response you get. I have a couple of inherited homes in a park right now that I listed on there and got hundreds of replies. Make sure you have your screening process in place and make it clear to the buyers so you end up with a solid tenant.
Owner financing is an option, but from what I've seen and heard from other park owners, the tenants will see it as 'rent to own' meaning you still fix things for them. It is common to default and then you're left with a vacant trailer possibly in worse condition. Basing your purchase solely on lot rent income can be a smarter approach, and then any sales will be bonus income.
You might also consider weighing the hassle of selling all the units and making sure people keep up their payments with finding a handyman to live in one unit and handle issues with the rental units?
Depending on the demographics of the area another approach would be to replace the oldest/worst units with new units through the CASH or similar program, and slowly upgrade the quality of the park/tenants. Someone who can buy a $20k home might be more likely to stick around and take pride in their lot than someone who buys a $2k home.