From memory (also been awhile):
Upper canyon is way more popular than lower (be prepared for crowds)- but it is deeper and is famous for the light beams you have likely seen in photos, although they are only present during certain times of the day, generally April to October-ish.
Tours are getting pricey, and require a pre-booking.
Horseshoe Bend, depending on time of year and weather, be prepared for in-your-face bugs, like a lot. Walk to viewpoint from parking is reasonably short, but seems longer if you have to fight the bugs along the way.
Camping, we stayed at Wahweap, which is around the lake, clockwise, from Page. Nice, clean place, with good view of lake. Also close to boat rentals.
Haven't been there in awhile, but apparently the lake has dropped considerably. Others may advise current status. Some great photo spots around the lake which show the color striations along the shoreline.
Marv