I left them in the workbench crate in angel cave. They were there before I left after the battle, and i used the long haul perk.
There are some sacks/duffle bags at the foot of a cliff near the site of the initial Whiteleg attack on the Happy Trails Caravan. Items stored in these will not disappear, and it is conveniently near the exit back to the Mojave.
Any of the Survivalist's bases make good places. Preferably one with both benches.