Again, see my review for details on renting a car in Juneau and the variety of things to see/do. Be prepared for changing weather - we had read about this in many Alaskan reviews - but when you wake up to sunshine you don't expect it to change so quickly! Juneau has a lot to offer and it is impossible to get lost while driving around.... you can only exit Juneau via ship or air!
Again, I ask that you read my detailed review. We did use up some of our time waiting for the bus outbound but we enjoyed talking with the locals on the bus and getting that local flavor. It would be neat to go later in June or in July when the salmon are truly running. That will have to remain on our travel list!