Another thing is, the sites that list the manufacture year showed that all the ones I was looking at were built in the 70s.

She is already is a customer of yours, which means trust has been built already. 

Most of that stuff is built on the sides of a mountain.

Not every trailer is built the same nor is every park in the same location, but more often than not they are a depreciating asset. 

We’ve already benefited from the rapid appreciation and from here on out, I think it will be flat or very modest growth. 

I have an opportunity to purchase a 2019 built 6 bed/6 bath 3300 sqft (Pool/spa, media room, full size garage) fully furnished STR in Encore Reunion community @ 180 per sqft costs me 600k.

Often low down payment/no PMI programs have those costs built in elsewhere in the loan. 

We converted a old restaurant on the property to a coworking lounge, redid the pool and built out the roof to a entertainment center with fire pits, lounges, bubble chairs, barbeque, large screen TV, music, yoga mats and amazing views of the ocean and city lights.It is designed for coworking/coliving for business professionals and entrepreneurs who want to...Live where they work.

Rome wasn't built in a day.The advice above about leaning into quality assets is spot on.

When one of my top contractors and I just started working together and we hadn't built up our current level of trust, we structured our first deal like this:-I purchased all supplies.