You are mostly looking at na and k as your basic needs, maybe magnesium and calcium, but you can just mix the amount of na and k dry required (use salt and lot salt properly measured) and add it to your drinks. You can buy little meth serving ziplock baggies on amazon and carry your powder portions to add as desired, or you can make up an amount in a liquid with other desirable things like calories in a shot flask and add squirts to your water bottle as you fill up en route, or drink and chase with your water/drink. I like the shot flasks for the longer rides.