I just looked at the Rach 3 score on IMSLP. It kind of scared me. So I think I'll stick with Totentanz, and maybe next year go for his (Rachmaninoff's) 1st concerto.
I'm playing the version on IMSLP, piano duet, edited by Emil von Sauer. The Rach 3 startled me so much because of the long passages involving incredibly intricate fingerwork, such as the one that begins after the first statement of the main theme in mov.
Besides, I would have thought that the actual first statement of the main theme would be the easiest thing in the whole concerto.