I Ace and collect all of the single-player Goodies in the "Boom Town" level.
The game is starting to get more difficult now that we have reached "The Canyons". The sections involving the Jetpack and Impact Explosives as well as the section involving the Orange Bird Sticker Switches are the biggest threats to Acing the level. (Though it is not shown in this video, since it would involve dying, misplacing an Orange Bird Sticker causes a row of Impact Explosives to fall and kill anyone nearby. I completed that sequence while Acing the level to add another layer of challenge for myself, but I highly recommend that you do it on repeat playthroughs so that dying isn't such a big deal.)
A number of Goodies are hidden behind various objects in this level, so make sure to look and jump behind objects and scenery to make sure you've gotten everything that you can.
When you're passing the thrusting stalactites while carrying an Impact Explosive, I highly recommend trying to stay low. That way, you decrease your chances of accidentally swinging the carried Explosive into one of the wider portions of the stalactites.
Revisit: No revisit is mandatory, but I separated the Cooperative Challenge areas from the collection of single-player Prize Bubbles to make it easier on myself.
This video covers the Cooperative Challenges (and their exclusive Goodies) in the "Boom Town" level.
I apologize in advance for any interrupting notifications, latency and abrupt loading screens. I have no control over them and they are simply the result of the online connectivity aspects of this game.
For the first Cooperative Challenge area, I cover both of the common ways for getting the items. I first show the "proper" way in which you use the grabbable carts and Impact Explosives. Then, I show the "improper" way in which one or more players can use Trigger Explosives to detonate the Explosives under the bank. Unlike many other Cooperative Challenges, you only get one try per playthrough to get it right, and the challenge is all the more difficult for that reason. Once the carts are destroyed, there is no way to try again without restarting the level. Thus, I present the commonly-known and easier alternative in case you are having too much difficulty with this Challenge but would still like the Goodies it has as rewards.
Special thanks goes to the random online players featured in this video. The player with the Neon Wireframe costume material has a PSN ID of Joshuafdz. The pink material female player (who only shows up briefly) is iM_PR3TTY_PRO. The other female player is TigerLily0587. I'm not certain on the remaining two players, but I think the character wearing a cap with a skull on it is mot651 and the lion with the Screaming Mantis piece is duckt12. I wouldn't call the last two confirmed, but it's my best guess from what I have. (I know, I really should use L1 more often to see what the players' names are. I wouldn't have to guess from evidence, timestamps and circumstances this way.)