I've never been that impressed at how cardboard works for weed suppression, unless it's left on for a LONG time, but I can't imagine that towels would be any worse. Sunlight probably penetrates towels better than it does cardboard, but the amount of sunlight under a towel has still got to be pretty small. I don't think that rain is going to smother anything, so it probably doesn't matter that it can get through the towels. If it doesn't rain, towels will allow the ground to dry out more than it would with cardboard, but that probably wouldn't make much of a difference to weeds unless it were REALLY dry (and hot).

I think the time spent with a decent hoe on a square yard of garden is probably similar to the amount of time needed to lay, and later remove cardboard (or cloth) on that same square yard.

Of course, many people swear by barrier cloth instead of cardboard anyway for permanent gardens. That is, places between established plants that you want to keep permanently plant-less. At least the cardboard decomposes and adds to the garden.

If you decide against towels I sure hope you'll take them to the pound/shelter. Dogs lay on the bare cold cement inside the cages. I know this for a fact. Just donated three old comforters. Pounds always need blankets, towels, quilts, and comforters.

If rain isn't in the forecast while you're on vacation it might be easier just to throw a tarp or a sheet of plastic over the garden. That it as long as you don't have any desirable plants growing.

Rodney