I have a vampire jumping script that only runs if the vamp is outdoors for height requirement reasons. But if I knew the indoor cell the player was in was high enough I could run the script indoors as well.

A cell doesn't have a "height" per-se, but I do believe its extents have a limit. If you're talking about calculating the height of a static room or something similar, I'd suggest that you use a couple of critters and getLOS to find it. I believe QQuix had an old resource on the Nexus that you could refer to.

I solve this scripting puzzle by firing a series of spells up from the ground and detecting the distance they traveled before hitting the ceiling.
Not perfect but it will do for now.