Yes. I was kinda hoping someone would ask this question, lol. Here's mine:

The creator of Say Cheese and Die!'s evil camera is Mr. Chameleon from The Haunted School

From what we know from the original SCAD, Spidey is not the camera's creator, but rather, he was the creator's partner. According to Spidey, this man was more evil than he was, and put a spell on the camera.

In The Haunted School, what we know about Mr. Chameleon is pretty vague, only that he was an evil photographer and that he hated children, and somehow managed to send a whole class of them to Grayworld via snapping a picture.

I don't think it's too unreasonable to believe that if the Say Cheese and Die camera creator could curse one camera, that he could do a similar thing to another. Only instead of predicting the future, it sends people to an alternate black and white dimension.

In the TV show's intro, they had the G floating all over town like the Goosebumps world was connected. I like to think of it that way. In one of the books (I forget which), there are dogs chasing a chipmunk up a tree, and I like to think the dogs are chasing Cooper Holmes. Fear Street was written this way (little easter eggs in unrelated books that point to previous books in the series).

This was confirmed in Return to Horrorland via a couple cameos and of course this is basically the biases behold the whole Horrorland series.

The TV did show that first, by accident though since they ended up re-using props like a Masked Mutant comic appearing in Awesome Ants for example.

When I finish the classic series, I really want to go through Horrorland because of this. I may go ahead and go through it at the same time because the classic series are rereads for me, and I've never read the Horrorland books. I love the idea of a connected world.