Wasted a couple of hours due to Google Map's error. For the past few months, Google Map's public transport routing algorithm has gone down in quality. I updated Google Map again in Jan 2019, it still sucks. On top of that, its schedule of SAM is old (last year). There were only 2 passengers on SAM. 2 others were waiting, but they gave up after the bus didn't show up at Google's predicted time. Mt Hood Express was ~60% full. I got off at Ski Bowl West a little after 10:10. There's a shuttle in the Ski Bowl parking lot which ferries people between Ski Bowl West and East (including picking up/dropping off at Government Camp).
The newly constructed Mirror Lake TH has a large parking lot at the west end of the Ski Bowl West parking lot, equipped with restroom (maybe dry). The trail goes down to Camp Creek, and then more of less flat, with some elevation gain later. I counted 9 brand new bridges sometimes over small ditches easy to hop over. Plenty snow on the trail, but very compacted that you can walk with just boots. I put micro-spikes on. The trail is in the woods. Some people brought sliding disc in here. I'm not sure why. It's not a worthwhile hike if you don't get to the lake (2 miles in). Right before you see the lake, the trail split in two. You can hike a loop around the lake. Take the right one to continue. 5 minutes after you see the lake, you'll see a well trodden trail up to Tom Dick and Harry Mt. I put my snowshoes on at the lake, but quickly took them off after seeing people coming down carrying their snowshoes. Put micro-spikes back on. The trail gets quite narrow at times, so it's easier to pass someone going the opposite direction without snowshoes. After going up for 30 minutes, it leveled up, and turned left.
Soon reached a steep but very short steep to the top. All the way clear tracks with plenty hikers. Great view of St. Helen, Adams, Hood and Jefferson. Very windy on the top. Difficult to stand still. So couldn't linger.
Back at the lake, had lunch by the lake. Warm, not too windy. Many people and dogs here. You can probably walk across the lake now, but I didn't. 
Looped back, and went down to the parking lot to waited for my return bus at the ski base. Read my book at a picnic table here.The link above shows 7.7 miles. My phone only registered ~15K steps, so cannot be more than 6 miles.
I boarded Mt Hood Express ~3:10pm, standing room only. One lady had about 6-7 bags (not snow related) piled up on the floor too. With these many people with gears in the trailer, the bus arrived 20 minutes behind the schedule. SAM waited for us. I was back in downtown ~5:30pm.
