In 2009, with feet blistered to, um, perdition, I nevertheless did Ballater to Banchory in a day.

The Deeside Way is easy walking, and you might like to consider making it a big day to get it all over and done with, and give you plenty of extra time for wandering around Fetteresso wondering where the photon the correct path is.

Plenty of accommodation in Banchory (or a wild pitch by the river, just upstream of hte bridge on the town side) and a really nice Indian restaurant.