I have no clue when it comes to figuring scale, so I'll post this here.

I am working with an average of 1.5-2" figures and I want to build a city block.

How can I figure scale for say 3 story buildings, lamp posts, traffic lights, etc??

HO scale stuff seems too small, and there doesn't seem to be much G scale stuff(that I can find)

Would 1:24 scale work??

HELP!!

2" we'll say = 6' so 1" = 3' or 1/36 scale (roughly) so, on average 10' per story would be 3.5" per story (roughly)

A 2 inch figure translates to a 5 foot 10 inch man in 1/35 scale. The 1.5 inch is close to 1/48 scale. They are not compatible unless you are using forced perspective in a box diorama.
To figure out what size you need, divide the real size by 43 or 35.

I am not going for 100% exact. I mainly set up dios for photography purposes. If I stick with 1/35 scale stuff I should be ok??

If the figures are indeed 2 inches, yes.