Need your ideas for day trips from Rouen, please!

Honfleur, Deauville and Cabourg are all picturesque towns. You'll need to check transportation from Rouen because I visited them while staying in Caen.

Rouen itself has several interesting museums and a rather large and beautiful historic district, which had to be substantially rebuilt after WW II. I spent more than a full day seeing Rouen itself, but I am a museum fan and I love to wander around historic districts.

The problem is that combining "besides the usual suggestions" with "totally reliant on public transportation" are counter intuitive. Trying to get off the beaten path usually involves not using the well-beaten transportation. And rural France isn't well served by "trains/buses" (same for most of the rural world). That being said, Paris is within two hours, and Bayeux is slightly over. If you are able to use a car, Abbaye de Jumièges and Château Gaillard are close to Rouen, and La Roche-Guyon is nearby—which I believe was the headquarters for Rommel during Germany's occupation of Normandy.

Amiens is a little over an hour away by train and is a beautiful city.

If you have a car, logistically you can go to La Roche Guyon. That town is parallel to Monet's Giverny.

In 1944 Army Group B under Rommel had its HQ in La Roche Guyon. I've been there once several years ago. At the time the Chateau on the hill had an exhibit showing Rommel's HQ, discussing the history, basically giving its portrayal of Rommel.

Rundstedt's HQ was at the Chateau in St Germain-en-Laye. He never had to fear assassination by the Resistance or bombing from the Anglo-Americans. He enjoyed from both a "hands off" policy.

If you're relying on trains, then I would suggest Cherbourg.

I agree with PharmerPhil, try to use a car, there are a lot of nice places around Rouen hard or actually not to reach by public transport.

Hi, Thanks for all of your suggestions thus far!
I will have already stayed in Amiens and I head to Paris for a week after visiting Rouen. I would consider renting a car if I had a travel companion, but traveling solo, it's just not something I feel comfortable doing. I didn't mean to imply I wanted somewhere off the beaten track, I'm definitely not the type of person who would skip the pyramids in Egypt b/c it was 'too touristy' :)
I love researching & planning, I just simply cant glean enough from my Rick Steves/Rough Guide/Frommer's books to make a final decision, so I wanted to reach out & see if I was possibly overlooking a town/city that the guidebooks may skim over. After more reading yesterday, Trouville-Deauville, Lisieux, and Bayeux seem to have made the short list. More reading to do!

The most comprehensive guides for French sites/sights are the Michelin Green Guides. My public library carries quite a few. You might check to see if you can hold of the Normandy guide.

I love researching & planning, I just simply cant glean enough from my Rick Steves/Rough Guide/Frommer's books to make a final decision

That's my problem too. I went to this region and some places I really liked, others i would have skipped, and that's after reading all the guidebooks I could get ahold of. So I go based on what I think I'll like and hope.

You can make a nice circle from Rouen with a car if you go to Etretat, then Honfleur for lunch, end the day in Trouville. I enjoyed all of these. Etretat because I like the ocean and it was a favorite site of Impressionists. Honfleur has a beautiful harbor and is a nice town to walk around it. Trouville because one of my favorite paintings by Monet was painted there (https://www.wadsworthshop.org/products/claude-monet-beach-at-trouville). The boardwalk is changed but you can still find the building with that steeple.

I had a car there as a solo driver and it was easy. The roads are well marked and I brought a GPS. In fact the only hard part was returning the car because the rental dropoff is under the train station in Rouen and the area is surrounded by one-way streets. I had to circle and without a GPS I would have lost track of where it was.