Here's a question I have about *current* Amtrak service to Fraser (WIP). If I take the California Zephyr to WIP to go skiing on any given day, is there a bus or shuttle that brings Amtrak passengers from the Fraser station to the resort? Even if the westbound CZ rolled into WIP on time (which is a BIG if for the westbound CZ), would the extra time needed for the shuttle ride to the resort make a day trip even worth it? If everything is running as scheduled, there's only a 5 and a half hour window.
I really don't think it would be worth it for the time you would be there. You would have to have all your ducks in a row and the train would have to be on time (dubious, at best). We never plan on skiing the day of arrival by train.
Would you rent ski's or bring your own? If renting - you can book them ahead of time, but you still have to go in and confirm all the paper work, get the boots fitted and the paper work finished (I am talking about doing this at the mountain - this would be the only way on that time frame). You will need to pick up your lift ticket ($95-$99/day). Then, baring any long lift lines you could be up and going.
The free shuttle system in Winter Park/Fraser is awesome. They use old school buses. It is a very efficient system, and for the most part runs on time. They are on a schedule - Here is a link to the schedule.
http://www.winterparkguide.com/maps/bus-maps. You would also need to give yourself plenty of time at the end of the day to check in your skis (if renting - rent from the West Portal rental store - you can ski to the bottom of the base walk a few feet to the door and check your skis in quickly.
Then the walk to the bus stop isn't far - but you do go all the way through the resort area. You would get back on the black route bus - making sure you give yourself time to get all the way back to Fraser - it has many stops along the way.
You could also set up a taxi - Valley Taxi is pretty decent, but they are very busy. Make sure they know you are on the train. I always call them in advance for the train pickup to make sure they are on time! Valley Taxi :
http://www.valleytaxiinc.com/
If the train arrived at 10:07 am (on time) and you caught the bus to the slopes - it would arrive there at 10:50.
The train departs at 3:50. You could be daring and try for the 3:20 bus and hope you got to the train. You aren't going to have 5 1/2 hours of ski time - maybe about 4 1/2 hours to get it all in.
I would really recommend staying at least one night for a less stressful ski adventure.