We need to compile a list of items needed to help us survive as float the estimated 60 days on a river. Survival can be broken down into three basic parts: food, shelter, protection.
Food and Water
Keeping food cold is out the question as we have no way to produce ice. A cooking source is plausible through a solar heating unit, it likely wouldn’t be able to handle daily usage. Dried goods, nuts, canned goods, pastas, grains, granola, fishing gear.
Shelter
Although July and August tend to have the warmest average daytime temperatures, the nights and unusual weather will bring the cold. Sheltering ourselves from the weather will provide reliefs from the mother nature’s elements. A conventional fire is a decent idea, although a metal container is needed to sustain the heat. Not to mention the need for wood, which we won’t have permission in most areas. Wind is a large factor in keeping us warm. Clothing and Shelter ought to be our main priorities to keep warm during the cold periods. Coats, sleeping bags, concealable interior, small electrical heating source.
Protection
Drifting into the unknown presents its own dangers. Protection from nature and man is necessary. Weather, water surges, animal predators and looters are all possibilities. Knives, flashlights, vests, emergency kits.