Hi Venturi,
I had the desire to the identical thing, but with my bird feeder. If my experience is any indication, you're lucky to get 6-10 feet out of the IR remote under sunlit conditions. I even tried training my "learning" remote control to the pentax signal, and it bought me about 6 more feet.
For this part, I'd recommend getting a wireless RF (radio frequency) shutter release, which can range in price from US$25-US$200 dollars. I liked my cactus (brand?) trigger (about US$35) until I lost my transmitter...
But the cactus trigger is definately cheaply made, though it did perform as advertised...
Adorama also brands/sells one that's about US$100 dollars, I may try this one, too.
As far as "standby" battery duration, I don't know if it's the same test, but I tried to do a time-lapse of a tent setup once using Remote Assistant to fire shots, 1 every 10 minutes. Granted, I hadn't just topped off the battery, but I didn't get more than about 9 shots. (90 min worth). I don't know if being "tethered" to the PC helped or hurt, but I would have expected it to last a lot longer. To overcome this one, I got the AC adapter for the K10D.
One last possibility, is to use "trap focus", where the camera fires the shutter when something moves in front of it that is in-focus. There are limits to this, too, search on trap focus to find more info, but this may be your easiest option. If you already have a locking cable release, you won't need to be there at all!
Hopefully the squirells won't run off with your camera!
-Chris