In Scagway we took "City and White Pass Summit" from Shore Excursions Group for 2:30 hours leaving at 8:00 AM. This was a good bus ride and we went into Canada for a mile or so. Lots of other people took the train ride and went to the first town in Canada. Most of them saw bears. We didn't.
The bus driver recommended that we have lunch at the Skagway Brewing Company. They don't start serving food until 11:00 AM but you can drink until then.
Their web site is here and the wikipedia page is here.