That I never came across yet fairly deep into the game so I guess I have something to do on my 2nd playthrough

Based on quick look on an off site there a lot of them around the wastelands?
which is weird they should have been placed in the towns where you would actually notice them...

I feel sorry for those who payed for the DLC i.e. used game users there's no clear description or mission that prompt people to the locations?

Yeah, they're almost too well hidden. I only found a couple myself - I looked up a guide for the rest.

Glad i bought it on PC so i don't have to worry about the sewers coming as DLC. If you can't find them use a guide to find their location. They are a nice addition to the rest of the game.

They were never meant to be easy to find. The intention of them was to be off the beaten path. I was expecting then to be very hard to find but I did 7 or 8. They were always right in front of me. If you just take your car to an area with a building and get out to walk around you'll find them.

Judging by how much I've missed so far, I'll be playing this game a second time with a guide.

So there are 9 of them... I watch the 2nd one on YouTube was pretty cool not long but still 9 levels for me to hit on the 2nd play through

P.S. Finding them on your own will take awhile plus add a whole new aspect to the game for those who don't have the DLC or missed em on 1st play through