If you want to see the Grand Canyon, rent a Harley from Eagle Rider in Phoenix. In 5 days you can do a big loop from Phoenix up through Wickenberg, Prescott, Cottonwood, Jerome, Sedona, Flagstaff, Grand Canyon, and back to Flag, then through Winslow to do the "corner stand" and a last stop in Peyson before returning to Phoenix. My wife and I did this loop in 4 days back in May, but we could have spent some more time in several of the places we stopped. You will not be disappointed in what you see on this route.
If you can make it six days or you can get started earlier than I did the 1st day, you might be able to squeeze in Tombstone and Tuscon or take in the North Rim or even hit Monument Valley.
The bike is $135 day including insurance. Hotels were average for touristy areas about $75 a night most places. Not sure what the laws are but there was plenty of wide open space with no one to tell you otherwise so I think Camping could be a way to minimize your costs.