D-Day & Normandy Hiking

les Grande Randonneé are a series of paths for hiking in France. Specifically, la Grande Randonneé 223 covers much of the coast of Normandy near the WWII sights. I have personally walked/run much of this path between Utah Beach and Sainte-mère-Église, which includes many GErman fortifications North of the wondeful Utah Beach museum. But it appears there are also parts of it that go along the other beaches, including Gold and Omaha. I believe it starts in Bayeux.

It will mean even more to you if you know the history of D-day, and which units were where. And this applies to anyone's visit to Normandy to see these historic sights. Here's the French site describing this route

https://www.ffrandonnee.fr/_314/gr-223.aspx

I don't know this guy, but he describes a hike he took along GR223:

https://cromwell-intl.com/travel/france/normandy/utah-beach-hike.html

Clearly you are pretty fit, but I would warn you that comprehensive visits to the beach and near-beach sites can involve a great deal of (mostly level) walking. In summer (what month is your visit?) parking can be scarce, making walking helpful in facilitating multiple site visits. It does seem (?) like you are asking about formal, marked trails for serious walkers.

We found that having a car for Normandy was essential for a multi-day visit. If you pay big money for Sergeant Rock to give you a personal tour, transportation is provided, but this area is virtually impossible to cover comprehensively by public transportation.

Although it is not a hiking bible, I urge a close reading of the appropriate pages of Lonely Planet France. It reveals much very local detail, if you read it carefully. The following two books may be out of print:

Fodor's Short Escapes in France, by Bruce Bolger and Gary Stoller, Fodors Travel Publications

French Gardens A Guide by Barbara Abbs, Sagapress. I mention this one because many of the Normandy and Brittany gardens are in extremely rural settings, and if you are content with roadside walks, you may encounter a location that attracts you. (And if you have paid for the garden, you could pre-arrange to use the toilet after your walk!)

Edit: Not everyone who posts here has our host's Rick Steves France book. He covers the Normandy beaches in great detail, with more than you can do in two days on the ground, without a guide.

I'd also HIGHLY recommend that you book a tour for the area. A good guide (many recommended on here--do a search) will make the area come alive. Otherwise you are just looking at some beaches and some ruined pill boxes. A guide will vividly describe who, what, how, why, when. WELL worth the cost.