Heather Lake - 4.6 miles, 1,030' gain
Besides the potholes that could swallow a Camry whole, this trail is a great way to get folks up to a beautiful lake without much effort. If you happen to be going in the spring, you even get the benefit of most of the rocky trail doubling as a stream. The start of the trail has your cookie cutter second growth forest but pretty quickly you start to find massive cedars that survived the saw. The monster below was probably 10+' in diameter and 30' in the air had a respectable tree and red huckleberry bushes growing on one of its burls. 
We made it up to the lake just before the clouds started to close in. Hikers arriving a half hour later could only see the lake itself. While we couldn't see up to Mt Pilchuck, the walls of the basin and the avalanche residues were impressive enough. Previous trail reports hinted that we just missed an avalanche a couple days before our visit... Something to try for next year.
Along the drive back down the highway there is a small brick structure that marks the trailhead for Old Robe Canyon. This short jaunt gets you to the upstream side of the canyon that you get to follow on the Lime Kiln Trail that was our tot's first real hike. I wont doubly bore you with the whole story of the railroad again but the short story is that it was initially built to bring gold and silver from Monte Cristo down to Everett and the canyon repeatedly thwarted their dreams by washing out bridges and tracks. The tracks were pulled and sold for scrap all because they didn't listen to their engineer and route around the canyon.
That process has continued with a rockslide blocking access to the last 0.4 miles of trail that would take you deeper into the canyon. As it stands now, you walk down to the river, get a little glimpse of what the canyon is like and have to turn around. Still worth checking out if you want to stretch the legs but will improve greatly if they decide to repair/reopen the lost section.
Random bonus trivia - while there are plenty of rivers in Washington that are blocked by dams or other man-made obstructions that lack fish ladders, the South Fork of the Stillaguamish River has a fish ladder to bypass natural waterfalls. This opens up about 57 miles of the river and its tributaries for additional salmon/steelhead spawning areas. Constructed in 1954, it was the world's longest vertical baffle fish ladder and feeds into a 300' long tunnel blasted through the granite. A very brave fish that first ventured into that darkness. Looks like a place worth visiting in the summer and then again in winter if you want to see what the rail maintenance crews were working against:
