I don't think that this mod idea would be possible without CK, but here's my idea:
There should be a craftable ham radio, which is used actually as a menu with options to send some of your settlers onto 'missions'.
In this menu you can assign settlers into teams. The more people you have on your team, the more chances of success for each 'mission'.
Those missions can be:
1) Scavenging mission. Assigned team goes into the random points of the map for random number of in-game hours, and when they return, they bring some random loot, like fans or duct tapes or other things back home. The more people you dispatch, the more loot they bring back.
2) Outer perimeter patrol. Assigned team goes on a patrol mission somewhere around the territory of settlement; this action temporary boosts settlement's defenses; any spawn points around the settlement are temporarily frozen (for a couple of days), making it safer for everyone to travel. If you send only one or two settlers, they may die in combat (random event).
3) Minutemen missions. Send your team to any radiant quest from minutemen (with a chance to fail based on number of participants).
When they are sent onto missions, you can check the crafted ham radio to see the "progress" and learn when approximately your dispatched team will be back.
In case you send your people to perform a minuteman mission, you can also participate and actually see your men running to the point of mission on the map and dealing with raiders/ghouls in the place of arrival.
In every case of missions they bring some loot with them which is automatically stored in workshop of the settlement.
Well, that's a base idea of what I'd like to see implemented in game, hope to see some feedback and suggestions from the community.