There is absolutely no way to tell, now, if you will have to wait in the line or if you will be directed to the bus. When you get to that area, you can judge for yourself. You can leave someone in the line, to save your spot, and you can go to the CM at the entry point (where the line actually is inside the roping que) and ask if you need to be in line or can you go right to the bus line. Keep your vouchers with you though.
I have to say that only one time have I found the checkin line to be really long....and that was the Sat that a ton of PopWarner families were arriving last year. The line was hugely long...but it only took about 20 mins to get through it.
I did have a wait of 20 mins in the bus line on Nov 29th though...got there about 5pm, no one in the checkin line, we were directed right to the bus line, and were the first in line. But.....our bus took forever coming. The CM told us the bus would be there in about 5 mins, when we walked up. But, 10 mins later, she came over and apologized for the long wait, telling us the bus was on it's way. Many others got on their buses...it was just the luck of the draw.