The Rubicon is around 18 miles long. Some say 11, some say 12, but a lot of people don't start counting miles until the rocks but the Loon trail head to Lake Tahoe is suppose to be 18 miles total. Several folks on Pirate claim a day run, some a 2 day but they say for average person, decent wheeler, never hit the Rubicon and not in a rock buggy, 3 days should be plenty to wheel, watch, hike, camp, ect.
Ill try and get some Google map stuff up in the next few days to show an idea of the possible routes. My map program at work is where I do most of my figures. It allows for Average speed, mpg, tank capacity, how long you want to stop and how often and other variables along with setting a start and end time for each day.