Google earth is your best tool but green trails maps are pretty good.  You will need the White pass #303 and Walupt lake #335 maps to get the whole unit.  Feel free to pm me if you have any questions,  I have walked about every square inch of that unit over the years and I have helped 3 friends fill bull tags since 2005, 2 muzzleloader and 1 archery.  My friends dad has a muzzy tag in there this year so I will be scouting around like always.