I have found a 16 space RV park with 20 mobile home slots, a live in 3br/2ba home, 10 bedroom hotel w/ laundry facility and last but not least it comes with 20 canoe and kayaks for guest rental.  

Suggest you only use your FHA mortgage slot to buy a 4 plex at your age in that location its about doors.

If a property appears vacant i will try to look in the front window, or even the mail slot. 

The cost is 168k It rents for 189 a night 1,100sqft Marina slot and fee is 200 a month.

I have heard of Lexis Nexus, TLO, and one or two others.

It has been many years since I've used an coin operated washer or dryer, but they used to be able to adjust what the amount they charged by putting something in the slots. 

I may have a filing obligation even where there is no income tax due.Each state is given pretty broad authority in establishing their jurisdiction (nexus is just the right/jurisdiction to deprive one of property essentially).So Ohio I know is complex because I had to prepare a couple.Basically for state income tax nexus is determined by situs of real property. 

If it's occupied, knock on the door.If it's unoccupied, tape a letter to the door (or slip one underneath or through the mail slot if equipped.As suggested above, talk to the neighbors.Ask at the post office what they know?

Today was slotted mainly for phone work.

I am not looking for a lockbox with a single code. i.e. each prospective tenant will show up at the house, after being verified,receives an their personal code which is good for that time slot of say 20 mins.