I found some Hi-Res FLACs of A Charlie Brown Christmas on RuTracker.
The many Hi-Res available include an SACD-R of the 2003 remaster and two FLAC versions of the 2011 remaster from HDTracks, one which is 24-bit/96khz and another one which is 24-bit/192khz.
I’ll get them while they’re hot if I were you as they all have only one seed each now.
I would recommend getting the SACD-R 2003 version as that might be the best version available.
I will download it and seed it for you as well.