There is a Stimpak on the ground in the Root Cellar.
Pick it up and consume it and you should go from level 1 to 130 in 0.1 seconds.
Made for own use cause i dont wanna level up all the way to all my perks and stuff on my 10,000th playtru.
So treating it as a NG+ kinda experience.
Now here is the kicker tho.
It seems that mods that give you XP or Cheat Terminals Level Up option cause stutters at 2 known spots(the bridge from Beantown Brewery to Cambridge and a spot just out of the settlement at Boston Airport at the height of the Airport Billboard)
When i went to Root Cellar and used Stim and then went to that Cambridge Bridge i had stutter there.
I found a really strange way to not have this and its the following:
Start game exit Vault 111 go to Root Cellar after helping Codsworth(or not) and pick up the XP Shot Stimpak.
Now use something like Cheat Terminal to travel to Beantown Brewery and go to the first stutter spot.
Now use Cheat Terminal to go to Boston Airport and go to that stutter spot.
Consume the XP Shot.
Now Fast Travel back to Beantown the normal way and if done correctly the DLC popups for the DLC quests should NOT have popped up on your HUD but the quests and radio stations are in your Pipboy.
There should be no stutter now.