We have cork in our master bath. It is soft on the feet and warm (compared to tile). We love it. I do not know how durable it would be for tricycle riding - it may depend upon the finish (we have ours finished to a high gloss which is gorgeous but I would not recommend for kids). The spills do not seem to be a problem. Cork cannot be installed over a floor with radiant heat. If you like a modern style other options would be rubber flooring (really cool, durable, soft and eco friendly) and linoleum (the old fashioned linseed oil stuff, NOT vinyl flooring) - it comes in a huge variety of colors and patterns, is durable (the color goes all the way through), not terribly expensive and is eco friendly. We put in in DS's bathroom (our guest bath).