Similar thread from a couple weeks ago:
http://www.bigwatersedge.com/bwevb/s...ad.php?t=25854
Garden sprayers are a good start, but they come with a sprayer that is too light of a mist.
My solution is to cut the tube and adapt to a dish rinser nozzel with hose from Home Depot for under $10
http://www.homedepot.com/p/DANCO-Fau...-202305850-_-N
Also, I think 2 gallons is a little short of the minimum amount of water that is functionally useful. In my exploration and testing of this same subject for myself, I found that 3 gallons is just about right. I carry a 5-gallon Sparkletts bottle as a backup refill source. 8 gallons is enough to share with your friends or serve you on trips longer than a day. It's enough to wash your gear & kayak, cool off, wash your hair and take a shower. You'll be all ready to go out for the night.
I prefer the simplicity and reliability of the hand pump garden sparayer over lightweight water pumps and other electric gadgets. With a hand pump we do not need access to the 60# garden hose pressure to fill a RinseKit.
The one I rigged up with the sink dish rinser is basically perfect for me as a gear and kayak wash system. The water flow and pressure from a few pumps of the handle is just right. I set my garden sprayer in an empty 5-gallon bucket for stability so it doesn't roll around in the back of my van, and because the 5 gallon bucket is handy to have along for multiple other purposes. I've never refilled my sprayer from my backup 5-gallon water bottle, but it's there if I need it. Dividing 8 gallons between two containers is easier to move around.
Remember, water weighs 8 pounds per gallon, so weight is a factor.