Hi, Scooper: Heading up the west side of the Sierras is much more complicated and, generally, considerably more traffic clogged. California has as many people as the entire country of Canada, and I swear that on a weekend especially, they all seem to be out in their cars in the "Gold Country," which is the western slope you'd have to traverse to get to the Tahoe area/Western Express, which has its own problems. Hwy 49 is the main west side road and, because of that traffic load, pretty nasty at times. There are other back country roads, but I'm unfamiliar with them. These would offer some brutally difficult riding, however, and some sections might be dirt. Others on this board will likely know the country better than me. On the Western Express, I was really unhappy with the Placerville to Fulsom section. If you end up heading up the west side, at Plymouth, head up into the mountains towards Fiddletown Rd/Shake Ridge Rd. to connect to 88. This will be steep but have FAR less traffic than the standard Western Express.
Hit Google Maps and have a great adventure.