I'm not a bluegrass banjo player, I'm an old time music clawhammer style player. So Cripple Creek is not in my repertoire. Of course I'm familiar with the tune, and to answer your question about the difficulty level on guitar...hmmm, I'd guess about a 6 on a 1-to-10 scale. Definitely a flat pick tune... I play guitar too, and prefer finger picking, but that tune just begs for a flat pick. I imagine any decent guitar teacher cold get you started on mastering that tune.

BTW, if you're not familiar with clawhammer style, let me refer you to Steve Martin's Clawhammer Medley: https://www.youtube.com/watch?v=sovTfNH4Lag

...and my all-time favorite Old Time tune, Julianne Johnson, which I've played for a local movie production: https://www.youtube.com/watch?v=uyXhu3dZUHw