Give 1-2 guest parties the option of renting a single room and keeping the other guest area locked via smart locks, then unlock the other bedroom with 3 guests for more and charge more for it.

I wanted to be able to come by, unlock boxes, collect checks and leave a receipt in the mailbox or taped to door/taped to drop box.

I'm able to lock/unlock remotely and change the passcode as needed.

They had left it unlocked, vacant, with the keys inside since they took possession 5-6 months prior.

The key is to really be able to spot, and unlock the hidden value of an asset (or create value).

I have a smart range which tells me when it's on and being used; smart door lock which tells me when it's locked and unlocked and I can let people in (or lock them out, if they're late checking out) as necessary; smart thermostat (Google Nest learning, which is an awesome thermostat), which I can limit the lower levels of cooling or upper of heating; smart ceiling fans that I can turn on, off or speed up/slow down as necessary; smart lights that I can activate or deactivate as necessary; ETC.

Or could I split the lot up and sell the additional lot and unlock value that way?

Unlock partial equity with LOC3.

If a neighborhood in an area where STR rents are higher votes to allow STR, they are unlocking a value increase by increasing the price which new buyers and investors would be willing to pay for houses/assets in that neighborhood. 

But you also unlock a host of other perks, benefits, networks, and tons of other resources with your BP membership.You are posting your request literally in the middle of the "field of diamonds" for real estate investors both large and small.