Like tallen said build your own or cut back on the pots used with the bigger system, build your own and save cash. Youre traveling so a larger reservoir is not a bad thing. Plants drink a lot of water plus it evaporates (1 to 2 gal a day or more late in the grow with 4 big plants) so extra gals of water is not a bad thing.
Picture your grow for a minute, you just mixed up a batch of nutrients and planing on going away fora couple of days. Your PPMs are 1000 they drink 2 gals of water that day. Next day the PPMs are over a 1000 because the water evaporates and leaves the nutrients behind. Plants dont uptake enough nutes to keep PPMs at 1000 with less water in the res so it rises. 2 gals gone the next day and another PPM rise, so on and so on, first thing you have nuked your plants.
Dont let me discourage you, there are way around this, I just wanted to let you know its not set and forget but it can be easily done if you have half a brain and a little cash. If you want to know more just ask.