Bah ZSR email notification has not been working. I should just check this forum more regularly!
BTW, what are past areas, really? Do we even know how they work?
-So areas are a bit complicated. Every area has multiple "states" depending on progress through the game. For example, Skykeep has 4 different states that have different doors, triggers, and enemies. In addition, every area has an alternate "past" map. When a timeshift stone is activated, the game will load from the alternative map in the affected region. This means that doors and such inside the timeshifted area are actually different doors. For most area, there is no alt map set, so the affected area will be empty. If you activate the timeshift stone in the Gorge in the state of the area before the dragon is there, there is no alt map set for that version, so the stone will create void.
This has been known for a long time. It is easily possible to skip the locked door in the Gorge using a BiT, but there is no known use. The key in the gorge and the one Golo gives are interchangable. The only thing you can do in the Gorge early is get the Tree of Life Seedling, but there's no point, since you need to go through the whole cart escort to talk to the dragon at all.
This is probably already known, but if you save while creating a new file from a corrupted file (BiT), you can create a file that loads directly into BiT.
-I'm not really sure what you mean. Do you think it would be possible to provide a video or clarify with more detail? I don't really understand the process of doing this trick, sorry.