If you can't find any maps in Lone Pine and you have a little time on your hands, drive up to the town of Bishop where they have a climbing shop called Wilson's Eastside Sports,
www.eastsidesports.com. They have all the topos you need and more. Plus you can stop by Erick Schat's Bakkery and pick up some really tasty breads, pastries, etc. Hmmm, I can't wait to get up there again. Sorry...
In regards to hikes to do before Whitney, I would hike the Cottonwood Lakes Trail, an easy-moderate 6 mile hike up to the lakes, 12 miles roundtrip, with only 1,000-2,000 feet of elevation gain, but it starts at ~10,000ft. The day before Whitney, you can hike 2 miles up the main Whitney trail to Lone Pine lake since a permit is not required. Then you can get an idea of what the terrain will be like and a feel of what to expect, although hiking in the dark is a completely different experience.
Here's another great site to checkout for more information:
www.summitpost.orgGood luck,
mj