My friends and I helped a kid with a pretty big tear in his leg (2nd person I've helped this year with a leg wound). I had the perfect first aid kit for him so we were able to send him to the hospital well wrapped. Like my injury the kid's was on a nothing part of trail but he got unlucky with a stump and ended up with an 8" gash all the way through the side of his calf.
You don't need a big first aid kit. It can be as fancy as some compresses, wrapping material, gloves and tape. All told, about $5 in stuff from a medical supply store.
Be safe out there.