Do you need the extra cash and is advancement that important to you? You sound very satisfied in your present job. Are you willing to give up that satisfaction for more money, chance for advancement and not working with the kids?
I don't know your age but I know that as I get older, the amount of money I make at my position and the chances of advancement don't excite me near as much as it would have when I was in my 20's or 30's. I much prefer to be happier in my work and make a little less, than to make more and hate what I do.
I'm not saying you'd hate your new job, I'm just saying these are things to consider.