Millersylvania State Park (map)
While I do not own a dog, I enjoy hanging out with them and their owners. I don't usually work on Fridays so I'm going to start exploring local short, not very steep (less than 5 miles and 500 ft elevation gain) trails, within about 30 min of Olympia on Fridays. Most of these trails are dog-friendly and little kid-friendly. If you are in good shape, you are welcome to come and hike at your own pace even though I will lag far behind you. If you are in not-so-great shape, you're also welcome to come and you'll be in good company. ;-)
Millersylvania is a lovely mix of old growth forest and rich wetlands. There are more than 8 miles of trails total but we will be doing a 3 mile loop with 75 feet elevation gain that provides a nice cross section of what the park has to offer. For those in good shape there are many side trail options to extend your hike.
To get there, take I-5 south to Exit 99. Take SR 121 southeast for 4.2 miles and turn right into the main park entrance. Parking is immediately on the left - look for me next to my white Ford Escape Hybrid with the bumper stickers.
@April: Carpooling would be great, just post a location that would be convenient for you. Perhaps somewhere on the westside.
@Scott and Amanda: At my usual rather slow pace, 3 miles of relatively flat trail will probably take 2 hours, maybe 2.5. But you're always welcome to go at a faster pace than me, at your own comfort level.
FYI, if you're coming from Centralia/Chehalis, it's actually Exit 95. Turn right at the end of the exit ramp and follow 121 North (and the Millersylvania signs) to the park entrance on the LEFT and the day parking immediately on the left once you're in the park.