Turns out you can very easily create your own Alternate Start in Fallout 4. It works just like in Skyrim, which is already detailed in this topic

For F4, just go to your Fallout.ini file and add the following in anywhere:

SStartingCell=SanctuaryExt02

Then whenever you start the game it skip past all the menus and go straight to a brand new game. It puts you in player's home in the wasteland version of Sanctuary Hills. Change the cell name after the = sign and it will start you in whatever cell you specify. You can put a ; semicolon at the start of the line to tell the game to ignore it, and remove it whenever you want to start a new character.

It starts you out as male. If you want to play as a female open the console, click on your character to select them, and use the following command:

SexChange Female

That will make you female.

Then turn the camera so you can see your face, and use this command to open the face editing menu:

ShowLooksMenu Player

You can edit your character as normal. But the option to change sex will not work (hence using the sexchange command above)

It automatically starts you with a pipboy and a vault suit, but nothing else. You start with a 1 in every Special attribute, which is not good. So you will have to use the the Player.SetAv command to set your starting attributes. Likewise you will need to use the Player.AddItem command to give yourself some starting items.

I have not tried it, but I am sure you can make a batch file to give yourself all the items you want, just like you can in Skyrim.

No quests are active, including the MQ. I don't know how that might affect other things in the game. As it turned out many things in Skyrim were dependent upon the main quest running, from getting in Whiterun's front gate, to bandit bosses wearing clothes. But it is definitely simple enough to try. I suspect that just like in Skyrim, you can use the console to manually start the main quest as well, if you really want to.

Wow, if Khajiit had Fallout4 on PC he'd try this when he got home! Thanks for posting this!

I created a Start Cell today, like the one I have for Skyrim. So far so good.

I placed a surgery chair in it (find it under Furniture ->FaceGenSurgeryChair). Make sure you have turned off any center camera mods or .ini tweaks you have before using it though. If you have one of those on, you will only see the back of your character's head when you sit in the chair.

You can do all of your face work in the surgery chair just fine. To get your body you can just stand up, pull the camera back so you can get a good view of your character, and enter the following in the console:

SLM Player (the long version is ShowLooksMenu Player).

You cannot get close enough to edit your face doing this. But you can do the body just fine.

I still need to do some work on the lighting for the start cell. Plus I plan to rework the containers. I tried taking a quick route and using the containers from the QASmoke cell. But they don't respawn, are not well labeled, and have very small amounts of things like ammo. I also found that the Legendary items container 'leaks' guns. Literally, they spawn under the container and fall to the floor. After a few seconds they vanish, only to be replaced by something else. It's raining guns!

So things are now looking really good for a player-made alternate start.