Thanks opushomes. This is now a duplicate thread - after five days I gave up and re-posted in the AC forum. Your comments are very useful - I think if I go through with the YPR-Jasper drive I'll have to allow more time: at the moment it seems to be 5 long days in row (4 driving, 1 on a boat). Alternatively I may settle for the coastal scenery on VI and the sunshine coast.
Don't think holiday planning has ever been such an embarrassment of riches!