Trip from Paris to D-Day sites and mont st miche?

I have a 8 month old child, and I would like to do a two day journey from Paris to see Omaha Beach and the cemetery, as well as Mont.St. Miche. Has anyone done a overnight trip from Paris and seen both these sites? if so, I would love some advice on how to make this work. I am leaning toward NOT going to mont st. miche for I don't want to be too ambitious.