Is it possible? Absolutely. Would I try it? No. I would allot one day for DCA and one for DL, although if I had just one day, I would do just Disneyland. But if you really want to go to both, I would start out at DCA. Head straight to RSR, and since you'll be by yourself, get into the singles line. Then spend the morning and part of the afternoon at DCA, hitting attractions like TofT (it's different than the WDW version, though I like the WDW one better), Califofnia Screamin', Monsters Inc.: Mike and Sulley to the Rescue, and a few others. You can hit TSM, though the queue is not as good as the WDW version. The line will be shorter, however. No need to wait more than 30 minutes for it. Soarin' is in better condition than the WDW counterpart, but watch your time.
Then head over to DL. You must see Space Mountain, Matterhorn, Indiana Jones, PofC, Mr. Toad's Wild Ride, and Rodger Rabbit's Cartoon Spin. I hear that the BTMRR is also great in DL since the complete refurbishment, so you might want to try that. HM is optional. It's neat because the stretching room actually is an elevator as opposed to the WDW version, but it's a slightly shorter attraction, and when I went, not in as good condition as the WDW version (this is rare. Most of the DL rides are in excellent condition, but WDW's is in better condition. Probably a more recent refurb, at least from when I went). You can also hit the dark rides in Fantasyland. Skip Splash Mountain and Winnie the Pooh as they are not nearly as good as their WDW counterparts. Star Tours is basically a WDW clone, and of course, Captain EO is the same.
Check to see if World of Color or Fireworks are running! California Law prohibits Disney from showing fireworks every single night of the year, same goes for Fantasmic with the fireworks. I would skip Fantasmic (it's different than the WDW version, the dragon is better, but you've only got one day). If World of Color is running but not fireworks, you may want to flip flop your day. You can still hit RSR in the singles line. That attraction is crazy popular. You've been warned. Someone else might know a little more about the exact procedures of when shows are running, especially since you are going in low season and they will most likely not be running every day.