There's a reason realtor purchase contracts are 10 pages, and they usually address the common issues that can arise. 

NOD-notice of default.

So as soon as tenant gave notice we started scheduling any needed work for that unit. and anyone leaving early we sent crew in immediately. 

I think (not positive) Brandon Turner mention in one of the podcasts that this is what he does and I am curious if this is common.

This will be your local flat fee eviction attorney and your go-to guy in case you need an eviction.Step 4 is setting up your rental criteria and a  process for screening and evaluating tenants.  99% of potential tenant problems will be prevented by proper screening.Step 5 is taking prompt action when managing your properties and you notice minor lease violations, late rent, etc. 

I personally wouldn't want to live with my tenants although I do agree with you that it is a great and rather common way to get started in REI especially if you have little money for down payments.

I am searching for items such as: Park Manager Job Descriptions 
Park Rules and Regulations 
Notice for rule violations 
Notice for late payments 
Introduction letter from new park owner 
Instructions for rent/utility payments.

While prices of investment properties should be based off of the actual rents received, or arguably the market rents expected, you will notice that properties with fewer units will be based more on comps than cap rates or rent multipliers.

If anyone is late, the rent is late for all "in common".  

The most common is 50/50 splits (80/20 and 70/30 are also used ).