Do we have access to the slopes/lifts every day of our trip?
No. Below is an overview of when to when the 6-day or 7-day ski pass is valid:
6-day ski pass is valid from Sunday to Friday inclusive
7-day ski pass is valid from Sunday to Saturday inclusive

Why is there no option to take a ski pass valid from the Saturday of arrival?
Due to traffic or weather conditions, the bus may be delayed, causing you to arrive later at your destination. If you have paid extra for a ski pass on the day of arrival and only arrive in the afternoon, you will have added a ski pass for nothing, as you will only be able to ski for half a day. If you would like to go skiing/snowboarding on the Saturday of your arrival, it is best to buy a ski pass at the ticket office. That way, you can see what is most advantageous and what you will enjoy most.