Hi Tom, welcome to the SOHC site, there is tons of great advise here on all aspects of a restoration. I may not be the best to advise you but I'm about 1/2 way done (optimisticly thinking ha ha) with my 73 500-4 and this is my first motorcycle rebuild. I started with the motor, mine was siezed, I ended up replacing all of the seals, rings, cam chain, gaskets, lapping in the valves and minor port cleaning. I have yet to see if it will start. Once that was done I started on the frame and I'm taking it one piece at at time. I'm somewhat budget constrained so I can only spend so much each month and I expect that it will take another 6-7 months if I keep up the same pace. Spring 2010 is my goal.
Depending on your goals and the condition of your parts it could be relatively simple or painfully slow (like my build).
Good luck and I'll try to keep up with your project build.