I've done a few games on the N64 back in the day, and while Nintendo had some unique features in their platform, it also had a bunch of limitations.  Texturing was obviously one of the limitations as the active texture had to fit within the 4K texture cache.  Which meant you need to load the texture cache and then draw all the polygons that used that texture, switch the texture in the cache, draw those polygons, etc. etc.

Also, since it was cartridge based, you needed to load the textures from the cart into RAM first, and then load it to the texture cache.  The cartridge was not like previous consoles, with you being able to use things directly from cartridge.

It also had a programmable processor for doing graphics (RSP), though Nintendo didn't open up access to programming it to 3rd parties until very late in the life of the console.  I always felt this was a mistake on their part, as developers could have optimized their renderers for their specific situations and make better use of the RSP memory and cycles.

Good to see you still working on this project, and I would say used whatever tools/hardware that is available that can plug into the cartridge port to make the best version you can.

Your garage looks a lot like mine Scott... old game development hardware in boxes.