(Scouts hike): Fastening karrimat and sleeping bag to bag exterior?

I know EXACTLY how you feel. When I was half my age, I went on a backpacking trip to Stockton Island, two hours by ferry out in Lake Superior. After getting off the ferry and waving goodbye until it returned two days later, I realized that my sleeping bag had slipped out of the bungie cords that I used to attach it to my backpack. I spent a mildly hypothermic weekend of nights in forty degrees with forty mile an hour winds on Stockton Island.

Buy a compression sack with straps for your sleeping bag. You can purchase additional straps to fasten your sleeping pad for a couple of dollars in the camping gear aisle of any department store or outdoor recreation gear shop. Use carabiners to fasten the straps to attachment points on your backpack. If you suddenly find an extra couple of hundred dollars laying around, then you can buy a 70 Liter to 90 Liter backpack to keep all of your gear inside pack compartments. I understand that not everyone has money to throw at new equipment.

Go Lite has a $99 sale on Terrono 70 Liter to 90 Liter backpacks, so you only need to find a hundred dollars to purchase a larger backpack.

Don't try to fit a square peg into a round hole.

You can find a large day pack with lashing points for as little as $40. Better yet, there are full backpacks, internal or external frame, for as little as $60 (check out Campmor.com). Best of all is to visit a local outfitter or camping store and find something that fits you comfortably.

My preference is for my sleeping bag to always be carried INSIDE my pack, protected as possible from getting wet. A foam pad can sometimes be put inside a pack unrolled/unfolded, so it conforms to the outside of the pack and all your other gear fits inside the pad.

If the top of the pack compresses the load you may place the mat and bag into a waterproof membrane(plastic trash bag)and strap it under the top compartment. Repair with duct tape as needed.

You don't have the appropriate back pack for the job. Buy, borrow or rent one for starters. Using gear that is too small or not designed for the job will result in lost and or ruined gear and a very sore back. In the event you absolutely cannot obtain better gear use rope tie downs or get straps to add to your existing pack. Simper fi!

not a good idea if there's any chance of wet or rain! hope it helped :D