Remove the poison fog from the poison cave, and replace the uranium and grimestone veins with pure raw uranium veins (kinda like raw gold in mikes mines and raw jade in the desert). Raw uranium veins would look similar to the large glowing green crystals in the walls of the cave, just smaller.
Raw uranium would have the special property of dealing a low amount of damage over time if the player is somewhat close to the rocks, increasing in damage as they get closer. The more uranium is near the player, the more damage they take.
Ideally, once the player gathers enough raw uranium into their truck, the truck itself would start becoming a hazard. The player would need to occasionally get out of the truck to heal, which in turn forces them to engage with the local goblins and skeletons.