Just finished up taking my legion supporter courier through Zion. The courier is energy and melee based with light armor and sneak, sort of a techno-ninja based tribal frumentari on VH hardcoe settings.
I enter Zion with my katana, chainsaw, laser rifle, sprtel-wood gatling laser and MF hyperbreeder alpha. The ambush starts and I return fire with the MF hyperbreeder alpha, since they do not have much if any DT, the white legs get cut down. I cross the bridge and come under fire, with the full auto hyperbreeder I fire a burst just as someone else attacks the white leg from behind. This new person takes a few to the chest and charges. I turn him to ash and fail every quest, it was follows chalk . As I intended on killing Joshua for Caesar anyway I decided to play it out. This made for a totally different experience than the normal Zion run.
At this point everything is now hostile, I made sure my quest selection was for something back at the Mojave so as not to point out where the map was. I then sneaked around trying to fend off the wildlife, hostile tribals and find a way out of the canyons with no shops or resupply available beyond what I could scavenge. I was able to make good use out of looted tomahawks and poisons for stealthy sneak kills. Joshua went down with a tremble coated tomahawk in his head followed by a DT ignoring chainsaw.
Without the quest marker I'd follow each stream until it ended in a box canyon, enter each cave to see if it led out of the Zion, all the while being hunted by tribals speaking strange languages. Without ED-E's enhanced sensors enemies could get very close so the best action was to stay hidden with tunnel runner to keep the speed tolerable. Giant Green geckos would two shot me as would giant cazadores. I had to be constantly aware and cautious. Using the MF hyperbreeder to conserve precious ammo, the laser rifle for stealth sniping and the gatling laser for giant geckos and cazadores who could both live through a full clip of the hyperbreeder and get me before it recharged.
Had a great time laying waste to all the tribes and finally finding the map to leave.
I'd strongly suggest trying a Chaos in Zion run just for the different experience, especially for a pro-legion courier.