why does he want to go there?
If you take into account every single one of his appearances it makes sense that he eventually leaves, he's an explorer at heart. even if you exclude Van Buren.
He lived as a scavenger making ends meet in The Hub, then he explores Mariposa with Grey (obviously)... So he's already an explorer but gets mutated. After that he continues to live in The Hub for awhile.
Possibly inspired by the vault dweller after the events of Fallout 1, he eventually leaves and returns to his roots
In Brotherhood of Steel, he's made it all the way out to Texas to a ghoul town (Los), and gets into it with Ruby the prostitute.
[I'm not going to talk about that stupid fucking quest about re attatching limbs]
After his time fucking around in Texas he returns to California and helps with Gecko, another ghoul town
even if you don't want to consider Brotherhood of Bawls, he still eventually left The Hub for Gecko
but why would he go to california in the first place?
He doesn't know about any health issues with bob yet... if there even is any, because we're excluding Van Buren. There's many reasons he may have returned to California, maybe he missed the Hub, or wanted to search for Vault 29
After the events of fallout 2, and with the NCR growing. Perhaps he was jousted from Gecko, or left on his own volition. There's no solid evidence for the fate of Gecko
He travels east... and settles down yet again for a short amount of time in another partial ghoul settlement (Quincy). Harold eventually joins up ranks for a small amount of time with The Midwest Brotherhood after mission 6.. which gives him more merit to be able to survive on his own
There's plenty of ways to justify his desire to explore.. Incorporating Van Burens idea only reinforces that point
how a crippled ghoul like him reached that untouched wasteland without dying?
Asking a question like that is very restrictive. But I understand why it needs to be asked, it's not easy to survive in the setting..
It's a lot more feasible for one person to cross the continent over the course of 200 years than a massive group though, It's not like Harold is one of the fuckin' 18 brotherhood expeditions east, he's an old ghoul who's lived almost his entire life in the wasteland, He's better off than most.
I mean how did he get from Vault 29 located... somewhere east, or in Southern Colorado (if you take Van Buren into account) to The Hub with no survival experience... at the age of 18? (if Vault 29 opened in 2090 like The Fallout Bible states) Hell as a mutant he can cross irradiated locations deemed unexplorable to normal humans.
Frankly this is open ended, but it's feasible considering his history. It's something that would have to be tackled when writing.
Harold is a great analog for a player character. Or he's a Post Apocalyptic hitchhiker I guess
Mcready is up north with his heavy body until he can’t walk his body sticks to the soil roots growing from his flesh to find water outside his thirsty body to become a tree on 10 december 2126
If you take into account your own write up here, Mcready becomes a tree around the same time Harold would join the Midwest Brotherhood. Providing ample time to have him travel out east, and for the Oasis Settlement to form both factions.
Of course though, it's your write up.. this idea does a better job than most fixing one of Fallout 3's biggest issues and I do like it.
but I like Harold