There are three Key Commands
Go to Beginning
Go To End
Go to End of Last Region
However it seems that only the first Key Command is available directly in GarageBand. THe other two are available when you use the Key Commands View in the LogicRemote app on your iPad.
There is one other kind of hidden command in the Transport Controls.
If you have Cycle Mode activated, then the Stop Button toggles between GoTo Beginning and GoTo CYcle Start. That is the one button with the arrow pointing to the right and the vertical line. You could place the Cycle Start to the location you need to jump to and use it as a placeholder. Ok I admid, that is a bad workaround.

Hope that helps
Edgar Rothermich
http://DingDingMusic.com/Manuals/
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