Up until 2016 I slowly remodeled the entire house efficiently.

I would always give them a call first before going down in person to the local office- many times the people you talk to on the phone can direct you to a more efficient way to obtain the information.

Please name some options and some good sources of information on how to do this effectively, efficiently, and most important, legally?

I include verbiage in my lease that allows for me to crack down on excessive use and, since I know how much it should cost each month, I have a great pulse on how efficiently people are using the home.   

Learning how to analyze a deal quick so the numbers make sense and then going to physically do the due diligence and then presenting that idea has been a challenge to make efficient.

As a general rule, if you can make a rate of return that is higher than the interest on debt, then from a money efficiency standpoint, you would want to do that. 

I'm thinking they make their money on economies of scale, efficiency and marketing. 

What ways have you found to efficiently track both routine (e.g. replace filters, connect with tenants, check gutters...) and new maintenance requests? 

Look into the efficient market hypothesis.

As it relates to offsite management (3rd party management) we have found that this solution only works if you have a a park that is already stabilized and running at or close to efficiency.