Getting all set up for the family and have yet to conquer this problem....thoughts?

Just in for ideas...

Ain't gonna happen. Just ain't gonna happen.....

lol....  

the answer is: eat it.

but immediate fillet and insulated dry ice would work.....that's how they do organ theft...jk

If you figure it out, let me know  Also, +1 on eating them where you catch them.  Mmmm...

I often fish in the Alpine Lakes Wilderness Area in the Cascades East of Seattle.  If I'm lucky, there's snow near the lake I can use to keep the fish cool on the hike out.

On shorter trips of <3 days, I gut my fish (keeping the head on), put them in freezer zip locks, then put that bag into a mesh bag which I put back into the lake, river, etc. to keep them cold. However, depending on the fishing, I usually plan to harvest fish on the last day so I don't have to worry too much about keeping them cool for a long period of time. It all depends on how long your trip is both in terms of days/miles. Keeping fish you catch on a backpacking trip just may not work out in every case.