Frankly, "Dracula's castle on the moon" sounds a little silly to me. I think the silly or gonzo element is what you & your players make it. I've been running Gamma World for the past several weeks using the game day module and now the adventure from the box, and it doesn't feel too silly. I am looking foreward to getting into Famine in Far-Go because I think there will be more story elements to explore. I have Legion of Gold, but I haven't read it. I think there is a moon base in that set though.
One of the biggest attractions of the game to me is that it is basically ready to go out of the box. I added minis for the PCs and their allies and cards for initiative, but that's all. I like the fire & forget nature of the play.
So, my advice is to try it as written first and then add elements that you want if, as and when needed. And have fun.
