Ammo can, narrow one. 7.62 / .30 cal behind the folding seat in the rear of the cab. hold enough to take about almost the entire truck. Pack it full of tools and top it off by stuffing the rest of the room with a rag to stop the tools from rattling.
Just jumping in on the band wagon. No way around removing the stump. there's a dozen ways to do it. stinks right now, but big regrets later if you don't.