His own transcription of his Lilac has a lovely tone and is quite manageable technically, and if you can deal with odd polyrhythm 3 against 5, I would suggest Prelude Op 32 No. 5
To some extent, if you don't mind playing a non original Rach piece, you might also want to try a transcription of the 18th variation from his "Rhapsody on a theme of Paganini", there are a few transcriptions out there provided for free and also the commercial version by Robert Schultz, which is the favorite one of many pianists