Helpful Sources
These websites all provide various playlists and track compilations of music that has played at the Disney Parks, both past and present. They proved invaluable in my compilation efforts.
MouseBits Forum
This park music discussion forum really took off circa 2011-2012. It maintains a great torrent seeding resource for many live recordings and several of the more commonly circulated, non-commercially-available pieces of Disney parks music.
Additionally, I've archived my MouseBits posts (at least, the more informative ones...) on the left hand side.
Disney Music Loops
Kirsten Wahlquist’s original site for all compiled park loops. The site has not been updated since circa 2005.
Magic Music Forums
Formerly titled Magic Music of the Mouse, this discussion forum is an especially great archive for park music discussions that occurred between 2002 and 2010. Even Randy Thorton, the former producer of many official park albums, made a consistent appearance to engage with members.
Passport to Dreams Old and New Blog
Site owner Foxx specializes in researching Walt Disney World’s Magic Kingdom, but several older BGM loops that they have uncovered are directly relevant to Disneyland.
Disneyland Resort Music Compendium
Michael Sweeney has compiled several MouseBits BGM listings to form a blog-formatted track listings resource. I have built on his efforts and tracked down many of the original posts that he referenced in compiling my own databases.
Disney’s Park BGM Lists
Although centered around the Tokyo Disneyland Resort, Star Orion maintains a smattering of BGM listings for the U.S. parks that are helpful to reference.
DisneylandのBGM一覧！|Disney's PARK BGM Lists
Capitol Media and Production Music
Thanks to the involvement of LA-area DJ Jack Wagner in the early music loops of Disneyland and Walt Disney World, the Capitol Records production music lines played an important role in Disneyland history and are featured in loops to this day.