Outdoor equipment suggestion based on situation/cost..

Here is the deal.

I have a 3 tap keg fridge in the basement that I love, hooked up to a 20lb CO2 tank.
On July 5th, we are having a large bbq, and I will have 5 beers ready to serve (it's been hard not to touch them...patience is definately a virtue). I thought I would allow access to the basement for the 3 taps, and have a serving box outside with 2 more selections on tap.
On the following weekend, I will be renting a cottage for a week with family, and would like to take brew there as well. Perhaps a way to make two kegs portable?

So, I need to find the most economical way to serve from 2 kegs, have it be portable, and able to withstand being outdoors in summer temperatures. I would like to avoid purchasing an extra CO2 tank and regulator, if possible.

I have a surplus of foam board insulation, so I was thinking of a 2 chamber insulated box that fills with ice, but I have no experience in serving kegs away from the keggerator, as well as cooling 10g with ice only. Can I get by with ice for cooling, and those little CO2 handheld injectors for serving, or would the cost of ice and CO2 cartriges equal the cost of a 5lb tank + regulator?

I'm a pretty good DIY guy(although I wish I was Yuri!) , but I need some advise on which direction to go.

Cheers,

Rhino

A big (clean) trash can will be the cheapest way to go. You will need about 3-4 12 gram cartridges to dispense each keg provided no one comes up and pulls the trigger and blows the cartridge. If you already have one of these setups, it will be the cheapest way as well.

You will need ice regardless of cartridges or a CO2 tank.