Yo man, so if you're flying and all you wanna do is ski I'd say try to stay up at the resort. Getting from Banff to Sunshine is a little drive and parking and the gondola and all the bullshit is actually dece wack there. Its extra money but if you and your homies just share beds or sleep on floors it will be hella worth it and all you'll need to worry about is goin skiing every day. There's enough food options up there it's do able and there's even a little bar thats open till midnight. But like you wont be able to hit the clubs.
Here's a link to the hotel https://www.sunshinemountainlodge.com/
ook it like immediately tho cause hotels get full then ur fucked. But yea call em and see if they have some rooms.
BUT if you prefer to stay in banff looks like they have a free shuttle
Flights I usually just hit google flights and they have the best prices and shit. Then from the airport they have some pretty decent shuttles. Here's a link to em
hope this is helpful! When in doubt just phone the ski resort, they pay people to help people like you to get there and have a great time. Also Sunshine is so fun in April so you will have a great time. For sure do it