Good route phil!
Apart from the headwinds.
Oh and the typical French lack of anything open in the last 60km - the shop at gambais was a life saver.
The view of the Seine at the top of the toughest hill of the day was spectacular and well worth the effort!
Last place I had marked as definitely open was the pizzeria in Breval, 45km from the end, which was indeed open. Longnes did have an open tabac but that was 200m off the route where you crossed the roundabout. Tilly had an old school water pump, just 70m off route, on a side road, Houdan had a range of cafes but off route and added extra distance. It's a difficult one as you always have to compromise between the distance ridden, and facilities along the way.
You will have noted that it was possible to avoid the toughest hill of the day by crossing the ridgeline about 3km away. But when I was researching, saw the sweeping curves to the road descent to the Seine and did a streetview I decided it had to be ridden.
On the way back I struck north from Gasny along the Voie Verte to Gisors. Gasny (going south it is the last place before the turn to Grommecourt and the toughest climb) had a large supermarket with a nice attached cafe, just 300m off the route. Note in the route sheet but perehaps missed by those on GPS.
I've decided I prefer a two day ride there (and back) anyway. So should I do this again I'd plan a route for two days, in which case some extra overall distance to take in more places for cafes would be good.
I did note on my alternate route back via Gisors that the centre of Gisors is a fantastic tourist spot for restaurants, cafes and shops. You've got bigger hills between Gisors and Forges Les Eaux (than going via the route I shared), but the Voie Verte between Gasny and Gisors is super flat. Over two days I'd be tempted to go this way on the way out with a hotel or camping stop (lakeside camping at Dahu just south looked nice) at Gisors or a bit further down the Voie Verte.