I can't say for certain who I'd like to see Clark on red k interact with most, since each time he's on red k, the character of Clark being on red k, changes...
Though I guess I'd like to see him interact with Jason Teague, since his character isn't offically dead. The fact that Jason nearly killed Clarks parents would most certainly stir up some anger. I also think it would be fun to watch Jason stand his own against Clark, showing that he is more capable than they potrayed him earlyer in the series when he was "pretending" to be someone he wasn't...