I would suggest looking at this video, it explains how to build an in game leveller www.youtube.com/watch?v=Oc6gACoELCE
or follow details below and it works for 3.0
Select Toy Box, New, Empty Toy Box.
When you enter the Toy Box press Options, Select Toy Store, Disney infinity 1.0, Toy Box Toys, Starting Toys - Page 11, Purchase Enemy Generator, Power Switch, Kill Switch, Repeater, Trigger Area.
Back out of everything, Press The Touch Pad. Cycle to Creativi–Toys section, Select Kill Switch and place it anywhere.
Go back to the Creativi–Toy section, select Repeater and place it next to the Kill Switch, Go back to the Creativi–Toys section, Select the Enemy Generator, Create a 3 unit box.
Back out of the menus and press the left directional pad to bring up your wand. (The wind is used to connect commands to objects)
Hold the LT and aim the wand at the Repeater, Press Square, Select New Logic Connection, Repeat. Hold the LT and aim at the Enemy Generator, press square, Select Random Boss. Repeat this process with all of the Enemy Generators.
This is the important part. You must save your progress before moving on.
Go back to the Creativi–Toys section, Select Trigger Area, Place the Trigger Area evenly across the enemy generators. Hold the LT and aim the wand at the Trigger Area, Press Square, Select Logic Connection, Entered, AI, Enemy.
Hold the LT and aim the wand at the Kill Switch, press Square, select Defeat.
Hold the LT and aim the wand at the Trigger Area, Press Square, select New Logic Connection, Entered, Player, Any.
Hold the LT and aim the wand at the Repeater, Press Square, Select On.
Everything is now connected! Enter the Trigger Area which will spawn the enemies and kill them instantly giving you XP every second. When the XP starts to diminish, Reload the save we made and reconnect the Trigger Area and start farming XP again.
You can also bring in another character to level up 2 characters at once.
You can also enclose the Enemy Generators with walls and let your characters sit there overnight to gain more XP.
Tip: If you leave your characters on overnight, rubber band the left toggle so the character runs in a circle getting all the XP dropped!
[Edited by rodpanther, 12/23/2015 10:28:16 AM]