Here is a short, and modifiable character generator... from the character's point of view.
(Deleted old version, new one below)
It works upto the 5 trainings are done.
I do not know how to format the IF statement to hide the trainings and open the next exit...
Currently just going to MainGame.
More steps could be added for the character to find some money and maybe buying starting equipment...
Then the start of a game.
(FYI... second "real" quest attempt)
Like it, use it, expand it if you wish...

Looks good, and in-character systems do feel better when possible. Some spelling issues, by the way, and it would look better if the command bar was hidden when not used.

To have it stop, create a new room, and an exit from Gen5 to it called "exit_training_done", and set it to not be visible. Then for the Gen5 room, change the before enter script to this:

ClearScreen
if (player.Trn < 1) {
  foreach (exit, ScopeExitsForRoom(this)) {
    exit.visible = false
  }
  exit_training_done.visible = true
}

Spelling was never my strong suit...
This didn't work for me...
Then, when I re-read what you said, I did not have the exit you called created, mine had a different name.
It worked after I fixed that.
Turning off the command bar did make it look better.
I've added a little and will link to the new version soon.

Updated version...
http://www.mediafire.com/file/kv2cwfwr1aio60k/CharGen2.zip
command hidden, until needed. (thanks Pixie for the idea)
Stats are randomized to ADnD's 3d6.
Add the rest if you want.
Train only 5 times, then you can leave. (thanks Pixie)
find coins, but no exit from there,
Spelling errors still there... (sorry)

Again, feel free to use and modify as needed for your game.
(I'm still learning Quest, and learning more with every bit...)