little guy said:soooooooo... would the "transition progression" look like this:
C F Am G7
C F Am G7
C F Am D7 (the transition from the key of C to G)
G C Em D7
G C Em D7
G C Em G7 (the transition from the key of G to C)
would this work as a way to transition back and forth between the keys of C and G?
Yes. Simple and direct.
I should have read this before I posted as you were already describing what I later suggested, sorry.
BTW, regarding transitions to new keys, a modulation is a different animal than a key change. Both could be called "transitions" although that term is more often applied to phrase structure than harmony, IME. You can always just change keys, especially to a closely related key, and don't really have to have a harmonic preparation and pivot chord.
I think it's good to stay loose about this kind of thing, personally.
Tim