I think another way to approach this could be a "Pay to Preview".
my thinking includes:
This is to be a one-time use since the intent is for you to experience the new content only and hence will not auto-complete prerequisite quests
Instead of giving the player all the prerequisite gear, we employ a similar technique to Duiviri where the player is allowed "loaner gear".
Since it is a "preview" the quest rewards will not be given.