Yes, 7 days would be enough. You would definitely have time to see some of the sights even if you are slowed down a little due to weather with 7 days. If I were you, I'd go to the tab about Roadtrips and use some of the online trip-mapping sights to figure out about how many miles you would need to travel each day to keep on schedule. Plan time for stops at the main sights you want to see and try to plan time for more spontaneous stops. You should be fine and it should be a great trip!