A new, wider bridge is being installed over Little Campbell Creek on the Coyote Trail (Tour of Anchorage) at the Campbell Tract - Bicentennial Park boundary. The work is being staged at Abbott Loop Community Park (sometimes refered to as the "Ballfield Trailhead). To get equipment and the bridge pieces to the creek, work crews widened and graded the bumps off the trail as it leaves the parking lot and drops down the hill.
Then it rained.
Now it's a bit of a slog on that part of the trail. So, steer clear and choose another trailhead. You can ride north on Abbott Loop Road to get to the Lore Road Trail and take that route into the park. You're on pavement for less than a 1/2-mile and get to avoid the mudfest. (See the book, "Mountain Bike Anchorage" for a description of the Lore Road Trail.)
From Lore Road Trail, you can access the new Lynx Trail which will take you to the Smokejumper Trailhead. Or, take Lore to Coyote Trail. Until the new bridge is done, there is a temporary, smaller bridge in place for crossing the creek, but you should try to avoid the area until everything is installed... and the ground freezes.