We did the Oregon coast for the first 3 weeks in September. We didn't reserve spots but in hind sight we should have. Several times we were getting the last few spots available. We thought especially by mid month that things would settle down but not so. Most operators told us they were a lot busier this year at that time than usual whatever that means. Don't worry about the hiway as it is mostly fresh paved so nice smooth blacktop almost the whole way. You just won;t make great time but if you a touristing who cares. We did most of our nights in the state parks along the way.