Here's my suggestion - make 5 gallons! (two will go MIGHT quick).
What most of us extract guys do is boil only 2-3 gallons, but we're boiling a concentrated wort. After it's been cooled, we add it to the fermenter and top off with more water to get our 5.0 - 5.5 gallon batch. Boiling ALL of your wort is only critical if you are doing an all-grain beer. You'll be going to basically all the trouble of doing a 5 gallon batch, but getting 40% of the output. As long as you have a 6.5 gallon or so bucket or carboy, there's really nothing extra that you need to make a full five gallon batch.
Plus, most extract recipes that you find are written this way.