sprint developer ? its easy to use, and mixes 1:9
or caffenol c, the ingredients are available at your local grocery store
and its as easy as 8 oz. water + 4 tsp. instant coffee + 2 tsp. washing soda + 1/4 tsp vit c.
i haven't used salt water to stabliize film instead of fixer but from all reports
you just need a super saturated salt solution and it takes a few days ...
and when you return home you can wash and refix them.
no need to take any photochemistry with you on your trip