I'm currently playing through Honest Hearts a second time but this time I'm taking the time to explore previously unexplored areas and taking the time to set up a temporary base of operations (though it may wind up permanent whenever I revisit Zion).

When I first played the HH DLC, I used the Angel Cave campfires, storage and work/reloading benches, but it never really felt like my own "home base".

So far I found the the Fallen Rock Cave (near the Dead Horses Camp) and the Stone Bones Cave (Near the Sorrows Camp) to be decent Bases on my second play through, thanks to the Bedroll, Workbench, Reloading Bench, Campfire and associated storage. I recently moved my gear from Fallen Rock to Stone Bones, because the path to all the crafting platforms in Fallen Rock is a bit twisty and confusing. Also the Stone Bones cave has a clean water source within the cave, which comes in handy for hardcoe mode.

I also took a liking to Cueva Guarache, because there's a "shortcut" to where the campfire and workbench is from the entrance of the cave. The only shortcoming is the lack of a Reloading Bench.

There's one caveat according to the Wiki, which is to make sure you clear out all the gear that is dropped on the ground and in containers, especially the ones you want to keep before you first leave ZION (after the HH MQ is completed) because the entire DLC area will "reset"

I haven't explored all of the caves yet, but if anyone has a favorite "housing/base" location in Zion, I'd love to hear about it...

The http://fallout.wikia.com/wiki/Stone_Bones_Cave seems like a good place and it comes with the added benefit of the Desert Ranger Combat Armour. Watch out for a few traps if you go exploring. I honestly didn't really stay long enough to need a base.