6" isn't too big, you can ask your LFS for large bags, possibly a shipping bag they came in with can help if the largest bag doesn't fit or a 5 gallon bucket with a lid should be more then sufficient.
A bag from your lfs should be sufficient. Ask for a large bag. It should be fine for an hour. My newest Knife was about a 45 min drive from the lfs that I got it at and it was a pretty easy going ride home. One time, I made an 8 hour drive home with a 5" RTCxTSN that was just double bagged.