Zones for Paris Navigo Passes and what card do you recommend?

Where are you going when you leave Paris vicinity? What day of the week are you arriving and what day of the week are you departing?

Here is a map of the fare zones
Villeparisis is in zone 5. It's FAR: is it free accommodation?
The cheapest way to go would be to get a Navigo Découverte (have a photo ready, 25x30 mm, cheap scan will do) and buy a weekly pass for zones 1-5 (the default)...except if your stay is Sunday-Monday because a weekly pass is valid Monday-Sunday (French calendar week).
In the latter case, you can go with Mobilis tickets at 20€/day (unlimited), or just get paper tickets: 2€ for metro/bus within Paris, 5€ for the journey from any Paris metro station to Villeparisis or back.

We are arriving mid week morning to Montparnesse. We chose lodging closer to the airport "just in case" and who will be providing a ride to the airport!! So: arrive Montparnesse around 11 am on a Wednesday via train. Store bags in locker. Do a little wandering around Paris. Back to Montparnesse, get bags, hit Metro 6 to RERB for our lodging. Next morning train back to Paris for a day wandering the city and back to lodging for journey home. Does that help??

It helps.
So, since you arrive mid-week, a Navigo Découverte loaded with a weekly pass is good. I forgot to mention that the weekly pass is only sold until Thursday, by the way!
You can buy it at the metro station in Montparnasse but be prepared to queue. To save time, one person could go to the luggage storage while the other one goes to the metro station.

This being said... you are wasting a lot of your Paris time with this setup. You would be better off with a hotel in Paris, in my opinion: head there on day one, leave your bags, wander as much as you want. Do the same on day 2, leave for the airport whenever you need to (unclear if you fly out on day 2 or early day 3).

Yes, then the Navigo Decouverte weekly zone 1-5 mentioned by Balso is the way to go. 30 EUR plus 5 EUR initial set up fee (I believe) per person.

parisbytrain.com explains what you need (photo) to purchase a Navigo Découvert

This is great information. Thank you. With regards to the concern about wasting time, We chose where we are staying specifically because we didn't want to commit much time to Paris and it was more important to be near the airport. Basically....it's a way to get nearer the airport with a day to spare for any incidentals (train strikes or otherwise) and any time spent in the city proper is bonus vacay time. We learned a while back that city time is not big on our agenda and is more of a "get near the airport" agenda :)

I see you have your mind made up, but are you not exchanging "city time" for "train time"? That is a lot of travel. Even doing that, you leave yourself open to being only near the airport the day you depart, rather than at the airport. There are a number of hotels at CDG, from where you are never more than a 10-minute ride to the check in counter using the inter-terminal rail line, CDGVal.

Staying one night in Paris and the second night at CDG, means you would only really need one RER ticket to CDG, 11.45€, rather than spending 5€ for a Navigo Decouverte card, potentially 5€ for the required photo, and 30€ for a zone 1-5 pass.

it can be harder to get to the airport if staying 'near the airport' than if staying in Paris. This is not a wise choice in Paris. There is no advantage to being near the airport.

Thank you all for that information. I am not sure how having a ride to the airport is not a good thing? and we really don't want to stay IN Paris so our options are limited. I had looked into the airport but was told it is loud and the prices were double where we are staying. I appreciate the help and opinions and hope what we are doing is not as terrible as everyone is saying !

good luck - I hope it all works out for you and you have no regrets

Thank you Nigel! It's vacation so while my plan may not wind up perfect or ideal, I am not working and am on vacation so there's always that :)