Jonesy said:
Also, if you're thinking of putting music from the originals, the music that plays after Belloq says, "Do as you will" in Raiders would play really well as Indy asks, "What is this thing?" in KOTCS. It'd be a nice transition to him and Mutt walking up the steps.

Tonally it would work, but I have to recommend not doing this, because the music playing there is a variation of the Ark theme, which made sense in the warehouse, because it was there, but now the focus is on the skull, and using that music wouldn't make any sense at all. I would really strongly recommend trying to find other music either from the KOTCS score or some kind of cue that doesn't have as strong an identity to connect it directly to something else.