We are driving from Connelles to Vernon to catch the train into Paris for a day. Is there parking at the Vernon Train Station? Are any breakfast items sold in the train station?
Its a paid lot, you may have o book and pay in advance on-line.
https://www.effia.com/en/parking/parking-gare-de-vernon-giverny-effia#
Looks like about 10 EUR/day. There is a Bar-Cafe on the other side of the station annex that may have some breakfast items.
Since Vernon is a Paris commuter station, get there early as parking space is limited.
If you're willing to park and walk a bit, the Boulangerie Rose on Albuféra would be lovely for breakfast items. The other places closest are fine but Boulangerie Rose is just particularly good. Maybe 5 minutes from the station.