That is basic info- here is my take as a park owner.I have had a park with this problem.

On the Op Ex side, STR's are basically a micro-hotel, so even if you are off on your revenue targets you have the ability to build other efficiencies in your business model on the Op Ex side that can offset any missed revenue targets and still have a good bottom line.  

Can't offer too much guidance without the basic info.

I've gained a tremendous amount of loyalty by just going in and making a couple of basic upgrades to set a good first impression with inherited tenants.

I don't use replacement cost, or rebuild cost. we insure for a stated amount. basically we self insure part.

@Greg Grant a pretty basic rule of thumb is to use 50% for expenses. 

I'm still studying the basics of CRE so need to look at a few case studies to get a better idea which way to go.

So apologies for asking you a basic question that maybe covered in this resource

This question is very basic, so you are best off using the search functions to sift through the forums as this topic is covered countless times. 

Saying that many people do deals this way may be true, but it doesn't mean it's the best course of action or most risk averse for someone who it sounds like is still learning the process and doesn't have the basic structure yet figured out.