Key to the Past

Key to the Past is a quest in Fallout 76.

Quick walkthrough
Acquire the following holodisk key fragments from various places across Appalachia:
 * Blackwater Bandits key fragment
 * Trappers key fragment
 * Diehards key fragment
 * Gourmands' key fragment
 * Cutthroats key fragment

Return to Rose so that she can produce a "master key" from those key fragments. Then go to the basement of the Pleasant Valley Ski Resort to find a raider cache storeroom with various loot.

Bugs

 * When leaving the world mid quest, some or all of the key pieces may be gone from inventory on relog, forcing the player to repeat the respective quest stages to acquire them again and be able to continue the quest. There is no known fix other than finish the whole quest during one session to avoid triggering the bug.
 * The bug seems to be triggered most often as a result of the game being quitted abruptly - by crashing, task killing or using the alt-f4 key shortcut. Avoiding those actions when possible and leaving the game world before quitting the game might help to prevent the bug from happening.
 * On the portion of the quest where you're asked to kill David, you will sometimes not be able to see a tracking dot showing you where Big Fred's BBQ Shack is.