I think the sweet spot is 4-5 bedrooms, 3-4 bathrooms, a fabulous Master Sweet (since they are likely footing the bill), sleeps 12 - 20, tons of activities (installed a pool table, corn hole game, etc...), and in my location of AZ a pool. 

Interesting question, as I am considering buying two four plexes on same street from same owner.  

Look for multiple owners who are actively buying.

However, I did a Google street view and looked at the whole street and it looks like all multiplexes down the whole street.

My wife and I are actively working toward this.

There is a lot of great information here on BP on the topic and many professionals in the field who are active contributors.

It's always a two-way street.

I helped a client sell an attached three-family property with no parking on Mozart Street a couple of years ago for a price which, at the time, I thought was crazy but the prices have continued to escalate since then.

You can also check HAR for active rental listings, or ask a real estate agent to pull the recent “solds” (rented) rental rates from the MLS 

For a change in ownership, simply change that first part to:I am proud to announce that ownership of 123 Main Street has been transferred to 123 Main Street LLC as of 03/18/2018.