If you're only going to be saving characters it's assumed the file paths will be referencing the runtime of origin so there's really no need for Textures and Geometries subfolders in your custom runtime. If however you are creating custom textures or original figures/props it's a good habit to not have your file paths all over the place, but rather get in the habit of organizing/saving this custom content to a centralized relevant runtime.
Also a good practice to save your custom materials as material collections in a relevant location for easy iterations and reference.

---

W10 Pro, HP Envy X360 Laptop, Intel Core i7-10510U, NVIDIA GeForce MX250, Intel UHD, 16 GB DDR4-2400 SDRAM, 1 TB PCIe NVMe M.2 SSD

Mudbox 2022, Adobe PS CC, Poser Pro 11.3, Blender 2.9, Wings3D 2.2.5

My Freestuff and Gallery at ShareCG