Assuming that you are fit and have camping gear:
Buy a cheap road atlas - the Phillips' one is good as it shows the approximate location of camp sites.
Draw a route on it after reading through other peoples routes.
Use
www.mapmyride.com to refine the route and get an idea of the gradient profile.
Make sure that you can get to or back from JOG by train on the appointed day split your train journey at Inverness. The tickets will be a lot cheaper.
Load the bike two days before the appointed departure date.
Have a pootle around with the fully loaded bike to get the feel for it.
Set of for the extremity of choice having divided the route into roughly equal sections.
Do the ride.
