Breaking the Bank
Head to the bank and attempt to open it. After getting denied, head to the marker to find a laxative. It is located on a rooftop so find higher ground and jump to reach it.
Head to the next objective point to kill Mad Dog to get his explosives. Return to the town proper and place the bomb on the marked location near the Grinders. Pour some laxatives on the bomb, then let the pup skag eat it. Then, wait for it to create a pile and check it to find the bomb.
Blow the bank open then immediately run away to avoid getting killed by the heavily armed guards that will respawn near the entrance. Kill them all then loot the boxes clean and head to the marked location. Kill the guards and hide the evidence in the specified spots. Turn in the mission to the bounty board to complete it.