IMHO, that's way too long and way too much. It comes across like you're trying to be the knight in shining armor come to rescue the damsel in distress. Very pursuing.
If you want to send a short note saying she's a great mom and you understand how rough it is for her now, that would probably be fine. You could also state that if there is anything she needs to let you know. Write your letter like you were writing to a friend. I doubt you'd offer to arrange and pay for a good friend's children to have a babysitter and chauffeur, would you?
Me 43 W 38 M 5 T 7 SD20 S15, S13 with 1st W ILYBNILWY June 2010 Separation/Bomb July 2010 Divorce Feb 8, 2011