This destination was originally supposed to be Spark Plug Mtn but the west side was so rainy we decided to try our luck with what we hoped would be a slightly drier scramble on the east side of the pass.   As it turned out, the weather wasn't any better, but the Rock Mtn. trail head is easily accessible and offered a good workout even if it isn't really a scramble (there is a trail to very near the top).
The first 1/2 mile or so is on a power line access road.  Take the first left (signed "trail") to an upper road.  The trail takes off from the end of this road and starts to climb, gaining 4000+ feet in 4 miles.  It was raining from the cars up to about 4200' and snowing from there on. The trail does a nice job switchbacking up a very steep slope, putting on the elevation quickly.  You'd want to be sure of favorable avy conditions for this route once the snow begins to accumulate.  Check NWAC for the avalanche forecast. 
At about 4800' the angle began to relent.  It was just above here at about 5100' that we decided to turn around.  One person had decided to turn around already (at 600' lower down) and two others were not planning to go any further.  The rest of us sort of wanted to keep going, but splitting the group like this isn't usually a good idea.  Too bad too as it was starting to look like the snow was tapering off a little.  We did about 4 miles and 2600' gain.