I'm working in the area system to see if I can revamp a few things. The first thing I did was convert the lo_*_vnum and hi_*_vnum to one simple range for everything. I went through and fixed up the code and it's loading fine. However, I noticed this range is never actually saved - it's calculated on boot every time. Would this be something better saved on the file?

As far as I'm aware, it has always worked that way. I believe that was what vassign's creating of a lo/hi room/obj/mob was designed to fix in the first place. To preserve the correct vnum ranges after a copyover/reboot/whatever.