Yes, ULA are one of the exceptions I mentioned. It covers fc00::/7 which is fc00 to fdff, though I believe most use just the top half. I use one for an intermediate network between my edge router and my primary firewall to not consume one of my limited /64 networks.
I haven’t played with IPV6 NAT much. I know its use is a bit discouraged as NAT was always designed as a stopgap measure for IPV4 exhaustion. It might be a good option if you need additional space and your ISP doesn’t support additional prefixes. Just keep in mind that if you use these in DNS, they won’t be accessible externally.
Make or find yourself a cart to drag around (g or G to drag it). It it doesn’t have wheels it’ll be quite loud. Sound = attraction = death in most cases.
Don’t bother with cars for a long while, even one that actually runs. They take a lot to maintain and cause a lot of noise (see above). You’re better off starting with a bike for midrange transportation (or if using mods a foldable bike).
When you start building or find a nice base area, make a crafting nook and drop all your items nearby to it. When crafting you can pull ingredients from 1-2 tiles adjacent.