As far as watering additionally every other day, you may want to remember that the less trips to your grow the safer it will be. Thus the term guerrilla/stealth. If you can find a close bank area and follow the simple plan I use, the plant will get all the water it needs. Try to stay organic if possible, too. That way you don't have a buildup of nitrates in your soil or the likelihood of it washing back into the water supply. Compost teas work really well. My grow is kept as close to 100% organic as humanly possible and it isn't lacking in anything so far as I can tell. You also come away with a quality product that burns into grey ash when smoked. No little black coal in your bowl or on the end of your doob because there are no accumulated nitrates in it.
Another thing to think about. If you do a little research you can learn what to use in your soil mix that will help hold water if you are not right by your supply. Peat mulch is a good one but there are several products that will work well. Compost mulch and manures will help a lot too. Water retention granules are available if you have the extra cash. I haven't tried the swamp tubes that @NBweedguy mentioned but I've read that they do work pretty good, provided you use them in a way that doesn't negate your reason for being as stealthy as possible.