Take the backstage tram to the Paradise Pier backstage area and go out the Paradise Pier security gate there, cross the street, and BOB is the Big Orange Building next to the Bonita Tower at the Disneyland Hotel.
I think it's called the DRC. Disneyland Resort Center or something. Most everyone in the know calls it BOB. Big Orange Building.
DRTSC is the name of the Walt Disney Travel Company/Central Reservations building on Center St. Promenade. Disneyland Resort Travel Sales Center, I believe. Hell, I used to work in that building and I don't quite remember the name of it.