Rolfe you have not been exposed to my deep reservations about the Tetrapharmakon, which you can read here.
So I'd phrase the question: Does the phrase accurately reflect Epicurean philosophy?
With that intro I'd say "enjoy what you can" seems correct to me, but "accept what you cannot" strikes me as too ambiguous -- cannot what? Cannot enjoy? Why?
I think I'd have to ask "why can't you enjoy it? Because it was totally beyond your power? Or because you didn't try?