Treasures are scattered in the area. After finding them, you have to quickly return them to your hideout before the time runs out or before you get damaged. If ever you fail to do so, the treasure will return to its original location and you have to keep trying until you safely deliver it to the hideout. It will help clearing out the enemies along the way to make your job a lot easier.
#1. Ten Gallon Hat
Southwest portion of the map. There's also a bottle nearby.
#2 Branding Iron
In the wooden platform under the bridge
#3: Street Sign
On the roof of the town hall. There's a bottle nearby so it's hard to miss.
#4: Bottle of Sarsaparilla
Beside the warehouse to the northern portion of the map
#5: Diamond Cactus
In the mine northeast corner of the map
#6: Temporal Flux Driver
Between the two small sheds in front of the middle-north building
#7: Bag of Cash
Jailbird Costume and Samurai Armor required
From the hideout, jump to ground level and look for a cage in the southwest side.
#8: Fake Mustache
Sabertooth Costume required
Follow the train tracks to the west and you'll spot a doll which you can grab unto using the sabertooth costume. Follow the path and you'll find this treasure behind a blue sabertooth door.
#9: King Monkey Love
Archer costume required
You have to ride the train and wait until you reach the wooden platform to the south, just before you reach the steel bridge. Shoot an arrow to the target ahead to find this treasure.
#10: Steel Horns
Sabertooth and Jailbird Costumes required
Head to the mine and climb the pipe that leads to a wooden platform. Jump across the rings and use the sabertooth costume to pounce on the doll across. Next, equip your jailbird costume and ride the iron ball to get past the laser traps.
#11. Golden Spike
Archer and Thief Costumes required
Past the steel bridge to the southeast, climb the electric pole and hope to the cliff where the bucket of arrows located. Just create a path the change to the thief costume to slow down time after pulling the lever to open the door ahead.
#12: Tacky Tombstone
Archer costume required
Find the supply of quivers in the covered bridge southeast. Just follow the path to find this treasure.