I am also curious about when/how an attorney/legal involvement comes into play with this.

I will always take a deposit unless I know the people involved. 

I've had a keen interest in investing for as long as I’ve been involved in real estate.

I don’t want much if any involvement because I’ll be doing other things.  

Challenge: It's in a neighborhood (no HOA), and renting the entire property (sleeps 25 in total) caused problems in the neighborhood, due to noise and parties – so we only rent the separate cabins now.

A little background about me, I have just over 200 doors in my current portfolio and our company manages just over 250 doors for third party investors in addition to those. 

Hopefully you can state simply (and truthfully)  at the end of the showing that you have other interested parties to whom you are showing the property and will let them know in due course.  

It can strengthen your relationship with your property manager and demonstrate that you value their contributions to your business.It helps ensure compliance with lease agreements.Many lease agreements require landlords to name their property managers as additional insured parties on their insurance policies.

He ignored several attempts and only got involved when we sought outside help but has again become unresponsive. 

This used to be a near-impossible task for a company like BiggerPockets, but technology and 3rd party solutions are getting better.