My notice states that I've changed locks and they must contact me to regain entrance.

Second entrance will be very situation dependent but I'd guess around 10-30k for a shoot from the hip answer.

It has an entrance from inside the home, and outside.

That way, it's a separate entrance to the basement which you can AirBnb.

I ripped this thing down to the studs, rewired nearly the whole house, upgraded from baseboard heaters to a full HVAC system, completely changed the floor plan adding a master suite, 1 bedroom, 1-1/2 baths and a 600 sq ft raised timber deck overlooking the valley, and I had to completely scrape tons of foilage and re-concrete the driveway/entrance (the list goes on and on).

Originally posted by @Patrick Liska:2 1/2 story, single family, 2 bedroom, Gas It's for sure at least a 2 family, it has 2 entrances and 2 meters..... 

The property: 4 plex stacked built in early 1900sBasement apartment with entrance at street level in the back.

This already has separate entrance to each apartment, each unit has bathrooms and kitchen, but not sure if it’s legal .Thanks.

High traffic road (route 1 maine) with highway entrance probably half a mile away.What should I look for besides the obvious?

The bathroom for 188-2 is in drywall and mud now it was originally a hallway leading to the unit but by moving the entrance and shifting a few walls I was able to create a new bathroom with side by side washer and dryer.