The version mismatch may be confusing, and may slow you down, but I bet it will force you to learn PhotoShop better than if you were able to follow each step exactly :-). If you are new to any PhotoShop at all, maybe you could first work through a map tutorial specific to CS6 - even if it is not a style of map you want to create, it could teach you the application better. Then you might be able to translate old <=> new better.

If you revise a lot, just the "undo" of any graphics software is probably already making you happy, right? Do you have a table so at least the familiar feel of drawing is present?