I did the 3 in one - helicopter into the bottom, trip on the river and then coach to two sites on rim (one with the opportunity to also take in the viewing platform if you wish to - I didn't see the need). Can thoroughly recommend the trip I did. Yes it cost a lot of money, but it's one of those once in a lifetime events. The worst thing I found was the flight in a light aircraft out to the Canyon - but that's just me! Helicopter was fab experience.
Enjoy you luck thing - I'm still feeling the benefits 4 weeks on.