Painting the Town

Painting the Town is a side quest in Fallout 4.

Detailed walkthrough
Talk to Abbot at the wall in the northwest part of Diamond City, against the green scoreboard. He will ask to retrieve a can of paint from Hardware Town. Passing a speech check can get Abbot to pay for the paint upfront or to give more caps.

It is not necessary to go to Hardware Town if one already has the paint in their inventory. The Sole Survivor may also already have the green paint if a radiant quest from the Minutemen leading to Hardware Town has been done and the Sole Survivor mixed the paint, as only one can is needed.

Exit Diamond City and head west to find Hardware Town. Approaching the store, a settler, seemingly in distress, will shout and ask the Sole Survivor for help. Follow them inside where a group of raiders will be waiting in ambush. Once the raiders have been killed, cans of yellow and blue paint can be collected around the warehouse. At the far back of the storage hall, there is a paint mixer that can be used to mix green paint using yellow and blue paint. Various ammo, loot, and valuables can be found in machines and locked chests around the warehouse. There is an issue of Picket Fences upstairs in the main office, on the desk.

Alternatively, one can enter through a loading dock behind Hardware Town. This will allow for a more stealthy infiltration, as the raiders will not initially be aware of the player character's presence. The Sole Survivor can clear out the basement first and work their way up through a hole in the main floor. The paint mixer is right by the ramp to the basement and can be accessed without killing all the raiders, though it may alert them to the player character's presence.

Return to Diamond City and use the paint on the wall. Painting the wall blue or yellow will result in a reward of 100 caps from Abbot. Painting the wall green will result in a reward of 200 caps (300 if passing all the Speech checks).

Bugs

 * Even after getting the miscellaneous objective to "See Abbot at the wall" to initiate the quest, one will sometimes not be able to talk to him. He will just speak his "I'm busy!" lines. Sometimes this can be cleared by going to Hardware Town and obtaining the green paint. On the other hand, if the green paint is already obtained before attempting to talk to Abbot, removing it from the inventory first may allow talking to him, though in this case, the quest may still malfunction. Disabling and enabling Abbot does not fix the quest. A way to avoid the bug may be by not making the green paint before meeting him and get the quest.
 * A possible cause is a quest objective for Quartermastery or Kidnapping being in Hardware Town, regardless of if the quest is active or not. Completing the quest seems to fix this issue.
 * You can try to resolve this issue by using the console command if you already have the paint. You could also try setting the stage to 10 instead of 20 if you don't yet have the paint. However, the setstage command does not seem to work for this quest if the situation outlined above is currently in effect.
 * Use the console command then 20 and then 30 to step through the quest until actually painting the wall is needed.  If needed get the paint from Hardware Town first and then paint the wall.  This seems to walk past the bug and Abbot finishes out the quest normally.
 * If the Sole Survivor has an extra blue paint can in the inventory after mixing with green paint for Abbott, it will be stuck in the inventory permanently, adding the weight of the paint can to the encumbrance for the rest of the game. Even upon completion of the quest, it still counts as a quest item, and therefore cannot be removed.
 * After having the paint mixer work in many different games, it no longer works, even when restarting games from scratch multiple times.