Are you looking into a brake swap out so you can fit 17 or 18” rims? If I ever end up with one that is the fist mod I’ll look into it.
No, not off-roading as much as being deeper in Colorado, where you will get a mountain goat, deer (not much damage), or the dreaded moose, which can total a vehicle. Also, unplowed roads with the occasional blizzard, Bullbars and Brush Guards are great. I like extra roof lights or lights on the guards for backroads so you can see wildlife before they cross the road. Usually, I use chains or belts for snow; no lift kits are big tires, too rough of a ride.
Have had brush and bull guards since the nineties (always with winches, Warn is my go-to brand), and I have helped many people and myself out of jams. I have deactivated front parking sensors on a Suburban and newer F150, but I haven't had the number of sensors or new cameras that a Rivian has. The accessories should come if you are selling a truck with excellent off-road abilities, but I have not found one yet, maybe the numbers aren't there for the secondary market.
With the Rivian being so quiet, I am a bit concerned that could be an issue of more on-the-road critters not running. We will see; supposed to arrive no later than July-September, they say, a white R1S. With these forums, I get the idea that most people are city folks buying these, and not too many go too deep or off-road, except to camp. Then again, at $70-!00K, that is understandable. I usually hold a vehicle for 10-15 plus years when I buy. Haul horses, not long distances, tired of buying gas, and everything on a farm uses it.