I understand part of your predicament, I don't have children, but I do have a '72 510 I need to finish before I get back into some serious building. Just can't do both at the same time without feeling guilty of ignoring one or the other. And if I had young ones, I would back burner my hobbies as well.
There will be time before you know it and you will enjoy it more with no regrets!
Enjoy your family!