Hi,
I had done this tours a few years ago but this time I was with my mother and felt it would be a good tour for her

From Sedona or Phoenix other tour companies do the canyon only ( ie you will probably get a bit more time at the el tovar/bright angel look out area so you could wander for a bit more time there ( and perhaps a few minutes hiking down the trail -but you would need to allow time to get back to the pick up point and may just have a picnic lunch and do not go to the Sunset Crater etc. Also the Bright angel area is probably the busiest part of the south rim and it is a bit quieter ( can still be busy at other viewpoints). I fancied the other 2 sights and the Desert view watchtower ( from there you can see the colorado river going north/south then east/west where as from the Grand canyon village you just see the eat/west portion ( and not that much of the river)
I would probably look at the tour descriptions to decide what tour interest you, The cameron trading post is also very good for shopping.

Regards

TBS