I finished the main quest and decided to take my brain with me, and after a peaceful resolution and completing all quests in the DLC i'm not getting any options to leave, am I supposed to go out past the pylons of death with the synthetic brain? Is there a tunnel? (I've been to all locations also, and I didn't see anything promising in any of the North, East and West tunnels.)

Any help is greatly appreciated and if it needs a patch I shall be anrgy :/

At the end of the main quest you get a weapon called Big MT transponder that teleports you between the mojave and Big MT

You should have got a new item called Big Mountain Transportalponder! when you finished the main quest. All you have to is just equip it and fire it and you're back in the Mojave.

I completely forgot about that lol, I tried it indoors but you can't teleport indoors, never tried it outdoors. Thanks yall