When I lived in SoCal, I'd visit the Last Grenadier in Burbank and All-Star Games in Diamond Bar. Both have a mix of new and used items, with the LG having the better overall selection,
IMO.
Of course, neither Burbank or Diamond Bar are next-door neighbors to Anaheim, but that's Southern California for you ... nothing is ever next-door to anything else.
Maybe a Google search with "Anaheim" and "games" would yield better results, but I'm not sure. I only ever went to Anaheim for GenCon SoCal.