You need a couple of weeks ...!
Spent about 5 hours at Pegasus Bridge & museum on Saturday just gone, personally think it is great. Even better as had just read the book by Stephen E. Ambrose. Museum does have a high personal content (plenty of family donations) which may not be your cuppa though.
Also did
Maisie battery between Omaha & Utah, trumps Pointe du Hoc in a big way in terms of relevance. Stuff is just creeping out of secret files after 70 years and seems the Rangers were (may have been/allegedly) told to go for Maisie at short notice before D-Day but ignored the order. And in any event their target was not Pointe du Hoc, it was actually another (third) battery whose name escapes me.
The American Cemetery at Omaha has a good museum - paid a return visit last Friday.
If you are going to spend time at Arromanches the PlayStore App - Arromanches 1944 - is definitely worth playing with in advance. and is a fair substitute (IMHO) for the museum there. Problem with the museums is they close at 18:00 and the App is 24/7. We navigated down to the beach at Asnelles (small signpost off D514) which is one of the App points of view. Almost definitely worth timing any visit to Arromanches to be at low tide so you can see more of the breakwater remnants.
Remember enjoyed
the Canadian Museum on Juno Beach on a previous visit - didn't make it this time though.
Personally was underwhelmed by both the Tapestry and Memorial Museum in Bayeux on a previous visit so skipped Bayeux completely last week.
I do make a pilgrimage to St Mere Eglise every time I have a chance (and again last Friday). Probably mainly because of the scenes in The Longest Day. But in fact is a relatively long way from anything else and is becoming pretty much a tourist trap so unless you have loads of time is missable.
There are tons of other museums around - Tank Museum, Reporters Museum etc - depends on your poison! Let alone various places for degustation of Cidre, Calvados et al.