please recommend a good Sierra climb, Western/Central area with decent riding "room"on the side of the road and moderate traffic. Would the Hwy 4 pass above Alpine Lake a good ride?

I can't think of a climb that meets both of your criteria. You can have one or the other, but not both. There's always Monitor or Ebbets Passes within easy reach of Markleville - neither has much shoulder, but traffic is moderate. These are classic Sierra climbs.

If you'd accept something lower down, there's a few ways to climb from Plymouth up into the Sierras. You could go via Fiddletown and up to Highway 88, then return via Omo Ranch and Aukum - that's pretty quiet for most of the route.

Alternatively you could always try going from Coloma up to Garden Valley, through Georgetown and up Wentworth Springs Road to Stumpy Meadows Reservoir. From there you can return the same way back to Coloma or head further into the Sierras before turning around.

Highways 88, 108, and 120 all have moderate to heavy traffic by virtue of the fact that they completely cross the Sierras. Highway 4 seems to be less busy up near the summit, but at lower levels it isn't much fun.

please recommend a good Sierra climb, Western/Central area with decent riding "room"on the side of the road and moderate traffic. Would the Hwy 4 pass above Alpine Lake a good ride?

OK, thanks norcalscot
i'll just climb Mt. Diablo since i've not done that yet (on a road bike)