We did it a an out and back.
Our original itinerary was:
Sunshine Meadow -> Porcupine Meadows or Police Meadows
Porcupine Meadows -> Lake Magog
Dayhike Nubbin/Nub Peak
Lake Magog -> over Wonder Pass - to Allenby Junction
Allenby Jct -> Porcupine Meadows
Porcupine->Sunshine meadow
There were originally 6 of us going. 1 bailed before we ever boarded the plane to Calgary. The two girls bailed the morning we were supposed to catch the shuttle up to the trail head. We had been car camping for 3 nights up near Athabasca Glacier & Kicking Horse and doing day hikes, and had been dealing with a lot of cold weather, rain, and some snow/sleet. They had enough, and didn't want 6 days of being cold on the trail.
That left three of us guys to hit the trail.
On day 1 there was snow on the ground and signs of active grizzly activity around Howard Douglas Lake.
We were worried we would lose the trail, but it remained clearly visible. The snow disappeared after we crossed Citadel Pass and descended toward Porcupine Meadows. Porcupine Meadows has little to recommend it besides a moderate distance from the trail head. It's a steep descent off the main trail heading toward Og & Magog, and there are no views down there. It's also a steep climb back up to the main trail again. We decided that on the return, we would not go back.
Magog Lake was busy as you say, but there are a lot of camp sites. The bear lockers and cook shelter were nice conveniences.
Ted was having a lot of trouble with his knee due to the steep climb down to Porcupine and back out, and we decided he wasn't going to enjoy the long route over Marvel and back up the Bryant Creek Valley. I really didn't have the heart to make him suffer, even though I felt he had been overly optimistic about his knee condition going into the trip.
So when we left Magog on day 4, we hiked to Og Lake. Day 5 we hiked to Howard Douglas Lake (securing a permit change from Banff via my Delorme InReach and wife who coordinated comms). On the way to Howard Douglas lake we met a grizzly about 70 yards away during a water stop. Fortunately, the bear wasn't interested in having a confrontation, so we went our separate ways without incident.
Day 6 we did the very short hike from Howard Douglas back to the trail head.
We actually had five days of excellent weather. We had some cold nights, but sun shine days. On the last day, winds and "wintry mix" accompanied us on our hike back out.
There were many hikers flying in to the Assiniboine lodge and camping. It was fascinating to watch these people at the cook shelter and see how much heavy gear they had. My two guy companions didn't mind being so close to the lodge once they learned that they could buy beer and wine between 4pm and 5pm and sit on the front porch drinking. Wasn't my thing, but it made them happy. I had cake and a coke, which made me happy!
Mt Assiniboine and the hike up to the nublet had terrific views. If I had to do it again, I'd hike straight from Sunshine to Og Lake on Day 1, and try to stick to the original plan of going over Marvel pass and looping back up Bryant Creek valley and out again. Maybe I'd pick McBride's instead of Allenby Junction for the night down in the valley. I read online later that it seemed to be a better location.
Howard Douglas Lake was a nice spot to stop, even though it was only 4 miles away from the "end".
We paid to do the 5 1/2 hour guided group hike up the Athabasca glacier. It was worth it. I'd been on glaciers before but others in our party had not. Don't go to the Columbia Icefield VIsitor Center though. That place is a crazy zoo.
So, too is Moraine Lake near Lake Louise. We did the Sentinel Pass day hike there regardless, because I really wanted to see Valley of the Ten Peaks.