I’m unsure if changing out the filter is required even if next people don’t want to spend money on replacing the filters. 

Hopefully, they just leave at the end of the term and it is a wasted effort, but it may be what chases them out.

I have a higher nightly rate because I can sleep more people, my taxes and insurance are higher.  

Why do people not understand this? 

Most of your money is in the stuff other people don't want to do.

So you may go through more people before you find someone hot for the unit to vet.

The second  problem is it is difficult to find people who will do preparation of the land for the mobile hand ,and also  I don't really know what is better/easier/cheaper...putting concrete pillars in the ground every 8 feet or putting down an asphalt or concrete slab.

It’s also annoying that you can’t obtain official cc&r rules until offers is accepted which is a waste of time! 

Sharpen your sales skils / people skills.

I couldn't imagine managing a property from out of state unless you had an extremely strong team of people in your market to help with showings, inspections, repairs, etc.