You'll find what you seek in comm.c (for smaugfuss 1.9).
Look for the following:
if( !sysdata.WAIT_FOR_AUTH )
char_to_room( ch, get_room_index( ROOM_VNUM_SCHOOL ) );
char_to_room( ch, get_room_index( ROOM_AUTH_START ) );
ch->pcdata->auth_state = 0;
SET_BIT( ch->pcdata->flags, PCFLAG_UNAUTHED );
You'll be able to make some changes starting at this location within comm.c
Also, you can change the ROOM_<whatever> in mud.h. Just look for ROOM_VNUM_SCHOOL within mud.h to find the section.