Ok, answering my own question but was an interesting experience so figured someone else may find this useful in the future.

We went from Seoul to Phoenix Park using a company called Good Bus. Very nice coach service and fully recommended. It stops at a number of spots around Seoul before driving to Phoenix Park and you pay the driver on the bus. It's worth getting someone who reads Korean to check their website for you as the pricing and information on the english one is incorrect.

Similar story for the Phoenix Park website, they have a very thorough Korean site but English one doesn't provide much information and also doesn't detail the accomodation packages that they have. Most of the accomodation at Phoenix Park is run by the park (Hotel, Condo's and Youth Hostel) but there are also a couple of small hotels across the road. If you can read and write in Korean (or a friendly concierge can ) then you can get them to become a member of the Park for you (it's free) and then you can access decent discounts (around 50%) on accomodation, lift passes and rentals.

Was quite warm there and you can ski until 10pm each night. Snow quality was ok, a little powder on top and packed underneath.

One thing to note is I would take all my own gear next time as the rental gear was terrible. When I put my 2 ski's together there was about a 5cm gap in the middle as both were badly warped.