I would use splash pants and mittens and just let them crawl around or put a play pen outside .... When we went camping with our 10 month old we took a large tarp and a heavy blanket like the ones the movers use to protect furniture.... And we put the tarp down first with the blanket over top so it was soft to crawl on and it worked great .... If you could keep them on the blanket with some toys it might work but I would have them dressed in splash pants in case