More Sigma DP2 & Pentax K20D experiments on the Potomac

Another early evening walk by the Potomac River, with Pentax K20D and Sigma 15-30mm EX DG lens and Pentax DFA 100mm F2.8 lens; plus Sigma DP2 used at the same time. Photos on http://www.flickr.com/photos/sandyfleischmann
The K20D doesn't seem to like big dynamic range shots, ie big sky plus darker tree areas, so I've been trying out the Cokin P-series graduated filter ND4 (06). I like the results on the Sigma 15-30mm EX DG shot (IMGP2407). I didn't use the grad filter with the tele- Pentax 100mm lens when shooting the trees on the MD shore across the river.
The DP2 continues to seem 'blue' or cold in color tone to me at its defaults, ie shooting it on auto white balance, doing minimal editing in SPP3.5.2. Actually the DP2 seems to me quite different from the SD14's more golden/yellow/green tones or the DP1 which mine at least seems to be warmer (more pink, magenta). But all these color variables I can easily edit to preferences in SPP3.5.2. I don't try to match the photos, I'm just learning what the cameras will tend to produce on output.
I'm thinking a lot about the light and nature situations we'll see in Washington state on the mid-October trip. And trying to decide what gear to take, cameras and lenses. I don't know what to expect on the 2 days at Mt. Rainier National Park (after the Seattle reunion we'll drive down there and hopefully stay at the Longmire lodge). Big skies for sure. Snow? (better not) Autumn colors (hopefully!)