Ok, so my main goal here is to be able to render the TI large font or small font in 8bpp mode at any coordinates. VPutS can do this, but in 16bpp mode. I'm wondering if there's a way to do this I just haven't found yet. If not, I'm not sure if I can directly access each character's pixel data, nor how to if I could. I am fully aware that there are libraries for fonts, such as FontLibC. But if at all possible, I would like to avoid using them because I prefer to write my own code before I look for working examples.

Well the toolchain itself has a set of string related routines for 8bpp with a default font:
gfx_PrintChar
gfx_PrintInt
gfx_PrintUInt
gfx_PrintString
gfx_PrintStringXY

And other related utility routines if you want to start there?