Distribute all titles with a one decision: "Distribute all Holdings"
To start, the player will see a couple new items in the Intrigue Decisions menu, the first being "Raise Your Banner." Clicking this will flag the province your character is currently in so that the primary holding there will be excluded from the other the titles you are giving away. You must "Raise Your Banner" on at least one province before you can use "Distribute All Holdings" (It won't let you otherwise - else you might give away all your landed titles and instantly lose!). To flag provinces other than your capital, simply raise troops on that province and have your character lead the army there, then use "Raise Your Banner" again. If you select the province, you can see a province modifier (a little green shield with a crown above it) showing that you have flagged it.
Women and children have not been forgotten. As a Female ruler, or as soon as a Regent is appointed to a child, your Marshal will take over the duty of flagging and unflagging provinces. The province flagging decisions for the Marshal act exactly like they did for the player, but are based on the Marshal's location instead. If you are given a job title by your liege your Marshal will also take over the flagging duties.
Now that your own primary holdings are secure and flagged, you are ready to hand out the rest of the holdings! Click the "Distribute All Holdings" decision and BAM! You are done!
When used, the mod creates a character the same way it does for "Invite Noble/Holy Man to Court" (that is: random traits, male only, same culture and religion as the player). However, in the mod, it doesn't cost you anything. This isn't meant as a cheat, or a feature to give you a leg up - I set it this way because I almost exclusively use the Search Realm function to find prospective vassals. This could easily be changed to have the same "Invite Noble/Holy Man" cost though, if you so desired.
The "Distribute All Holdings" decision fires off an event that hands out up to 30 lower titles (baronies/cities/bishoprics) at a time. This is probably overkill but it should ensure it gets them all with one run. The same event then gives out up to 10 County titles (province primary holdings). Yeah, it's a big event. If it doesn't get all your holdings the first time (you've accrued more than 30-40 titles), simply click it again..
As with almost all Crusader Kings 2 mods, simply put the downloaded files into
C:\Users\User_Name\Documents\Paradox Interactive\Crusader Kings II\mod