Thinking your best bets are in Southern Dutchess and Northern Putnam Counties. As you mentioned,
Wappingers Falls is a location worth investigating. Based on your description, I think
Fishkill and
Beacon are also good options in Putnam.
Cold Spring is also worth a look.
Located in Wappingers Falls is
Bowdoin Park, offering lots of room for walking, exploring, and marveling at the views of the Hudson River and distant Catskill Mountains. Wappingers Central School District serves most of Southern Dutchess (Wappingers Falls, Fishkill incl.) excluding Beacon. Good district - your children will get a great education here no matter the district. The New Hamburg train station serves Wappingers Falls with a ride in to New York ~1hr 40min. 10 minutes to POK.
The Village of Fishkill is walkable and has many neat shops and restaurants. The
Town of Fishkill is one of the fastest growing in NYS. Train station less than 5 miles away. 15-20 minutes to POK.
The City of Beacon is another fast-growing place - lots of people moving up from the city seeking some peace and quiet. Major commuting hub on the eastern shore of the Hudson River -
Beacon Station. Beacon sits in the shadow of the hikeable (and endless source of outdoor activities) Mount Beacon. Schools are good, perhaps slightly less so than WCSD (this is a
city district after all). Beacon is quite the artistic spot - major art gallery in town
Dia:Beacon. 20-25 minutes to POK.
Cold Spring is an affluent NYC suburb in the north-easternmost part of Putnam County. It is a bit more expensive than the aforementioned locations in Dutchess. Village is really nice - antique shops, nice restaurants, tremendous views of the Hudson, and excellent schools. It wouldn't be hard to find a place with land here, especially on the outskirts of the town. Has its own train station - 1hr 10min all the way. 30 minute commute N to POK.
I typically recommend that people try to get as close to the Hudson River as possible when moving to the Mid/Lower Hudson Valley. The Hudson River and the surrounding terrain is unique and remarkable. Of the 3 locations I just provided, Wappingers Falls, Beacon, and Cold Spring are all right on the Hudson. Fishkill is about 3 miles away.
You would likely find Rhinebeck and Red Hook intriguing but they are farther away from NYC and out of Metro North's service range. Arlington is worth looking into IMO. Really good schools and ~5 minutes away from downtown Poughkeepsie.
Other places like Carmel / Pawling / Brewster are nice too, just a bit farther away from the Hudson and your husband's place of work.