Happy travels Rogue! We'll miss you.
Incidently, I will be on the road as well next week, for about a weeks stay. Also, chances are I will not be posting as much as usual for a little while.
Super Mutants? First we let in Gruug and then it all goes to pot! Yes, I agree with Gunslinger, with the exception of Gruug, who is a very exceptional case, the super mutants are really part of this. The Masters Army is far to the West of where this story takes place and its unlikely the Super mutants are even recognized. This has been part of the problem of bringing Gruug in.
So McReady probably wouldn't know a super mutant if it came out of the toilet and bit him on the ass. The only characters that might are Blade and Buffy, and that's only because they have migrated far to the East before coming into this story.
But- that said, the creature could be something quite similar if different.
Syphon please give it an edit but you need not give up on this post totally. But you will have to come up with a replacement bad guy. Some kind of giant humanoid would work.