Driving for dollars, calling ads on CL, knocking on doors, are some of the things we've done that have proven pretty effective. 

When I have a much larger portfolio at some point it will be done.

If a tenant asks for access to personal property, open the door and grant a full day to remove items (assuming not a threat to property damage). 

Some work I would need done would be some tile replacement in a bathroom shower, a leaky sink faucet replaced, and kitchen fan replaced / fixed, and possibly (I am undecided here, depends on how much the previously-listed runs for cost) some framing done - My property was originally built as a single-family home and split into a duplex, but shutting off / sealing off a door, which is still a door.

I have a few single family properties that are rented out and I am looking to go into the larger multi unit property space (possibly a large apartment complex).

I would like to buy, hold, and rent out this property until I can leverage it into a larger deal. 

Seems like just knocking on the door would be frowned upon.

Add a door separating the "new area" from the old area so it acts like a separate unit.

I am in early discussions with the owner of the lot next door to purchase that lot as well.

Perhaps look at renting a place where you want to live and put your windfall into a commercial property or team up on a much larger deal.