Frio wallet is the answer for me
I like the Frio because it's not necessarily meant to keep insulin cold but rather at a constant temperature - this is the important part. They come in different sizes to accommodate your supplies, too. I have 2 insulin pens, 1 for Rapid and 1 for Levemir. The wallet I use holds 2 pens. It's as easy as soaking the inner liner for a couple of minutes (swells the crystals inside) and you're good to go for a couple of days. Just soak again for a few seconds if it starts to dry out.
Keep everything together: test meter, strips, Frio wallet with pens/insulin vials, needle tips, alcohol swabs or hand disinfectant and candy/sugar for lows... in a fanny pack or small lunch cooler bag (if you can wear it - the better). That way everything is always with you and easy to carry.
You can do the same thing without the Frio wallet by keeping it all in a special cooler. Wrap the insulin and put in zip top plastic bag if using ice or gel packs to keep cooler cool. Watch that the insulin stays away from the cold source so as not to freeze or get colder than acceptable. Again, the idea is to keep the insulin at relative temperature and avoid wide fluctuations.
Hope this helps and have fun camping!