You've come to the right place to ask. A mini bus tour including Utah beach - St mère eglise - point du hoc - Omaha - Arromanche is 70€ lasting from 8:30 to 18h. Not easy to get there on a train for that time. I beleive the first train arrives at 9:20 You do an afternoon trip Arromanche - Longues guin battery American cemetery Omaha beach for 35€.
There are two mini bus tours operating from Bayeux 'Bus Fly' and another. I quote Bus fly as I sometimes work for them if they are overstretched.
I don't knox the tarif for a taxi for a day. I think it must be quite steep.
I can quote my tarif for the day at 240€. Driving included.
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