After completing the Special Tour, the intelligence of CPU characters selected by the player can be raised to S rank by pressing + on the character select screen. (This has no effect on characters who are already S ranks, of course.)

Unlock the following Boards by performing the corresponding tasks:

BOARD - HOW TO UNLOCK
Alefgard - Unlock Special Tour.
Alltrades Abbey - Finish in first place in The Colossuss in Tour mode
Bowser's Castle - Finish in first or second place in Super Mario Bros. in Tour mode.
Good Egg Galaxy - Finish in first place in Bowser's Castle in Tour mode.
Special Tour - Complete all Dragon Quest Tour and Super Mario Tour boards.
Super Mario Bros. - Finish in first or second place in Alefgard in Tour mode.
The Colossuss - Finish in first place in Good Egg Galaxy in Tour mode.

Unlock the following characters in Tour Mode by performing the corresponding tasks:

CHARACTER - HOW TO UNLOCK
Dragonlord - Place 1st or 2nd in the Alefgard board.
Jessica - Place 1st or 2nd in Robinn' Hood Ruins in Tour Mode.
Patty - Beat all the boards in Special Tour
Peach - Place 1st or 2nd in Peach's Castle in Tour Mode.