Well, if you wanted to break up the drive, you could go back toward corinth, jump off to see the canal, then go to Loutraki on the Isthmus, a little resort town, for o'nite stay. If the weather's nice you could sunbathe on beach, boys make sandcastles.

OK ok dumping Mani Peninsula. Does one more night in Nafplion make sense. I am fine with not organizing every last detail... but my husband gets stressed out without all the sleeping arrangements booked. Hence I am harassing you all to help me figure this out. Believe me I appreciate it.

It does actually make sense, with the short time you have there at the beginning you will be travelling to the surrounding sites, the extra night there you could spend those few hours in Nafplion itself.
Sounds like the plan is shaping up now
It's been tough choosing, but you'll enjoy what you do see & you now have a list of places ready for a return visit!

Yes, it looks to me too like your plan is shaping up. I'm not sure whether it's better to have everything planned to the last detail, or to leave a little flexibility in your plans so you can stay a little longer somewhere you enjoy, or to allow for unexpected delays. Certainly around the Easter week it would be wise to have everything booked well in advance. I am the spontaneous type, and usually alter my itinerary during the trip.