No problem taking any of your companions along.
I assume they took a lot of Rad-X.
That's LOYALTY man.
Heh...I got there, because the quest marker was like, on the fringe? Then it kept moving, and I forgot to bring the Hazmat suit.
Thankfully I had like...25 Radaway, and didn't meet much in the way of hostiles until I got to the crater and Virgil.