Walden Parke Preserve is managed by the Bangor Land Trust and is part of a large complex of contiguous preserves (including Bangor City Forest, the Penjajawoc preserves, the Veazie railroad bed and Caribou Bog).
I hiked the preserve this morning before work. The preserve itself is quiet and wooded and the trails well marked. The kiosk at the parking lot did not have a trail map, so I would recommend downloading one ahead of time from the Bangor Land Trust's website here.
Like many of the parks in the area this time of year, mosquitos were abundant so I would recommend bug spray and a head net.
Here is a map of my hike.