We took the train trip before last, this time (about 2 weeks ago), we used a private tour that included a full day, stop for a hike, go to the Anchorage Wildlife Conservation Center, etc. About 6.5 total I think, but wanted do try it instead of just making the straight drive. It wasn't the cheapest thing, but since there were 6 of us, it was well worth it.
Believe they also have just small group (shared) direct transfers as well since when our sprinter van showed up with the name on the side different groups of people showed up. Company was called Welcome Anchorage, I think they are relatively new, but were great.