If we cross the Pont Neuf and turn left to walk along the Seine to the Louvre, what is the best entry by foot (with museum pass in hand). There appears to be a three lane freeway etc and wonder if walking is very feasible.
A 3-lane freeway? I don't think that I have seen one of those in the area that you mention. When you cross Pont Neuf, you turn left on to Quai du Louvre which turns into Quai Francois Mitterrand. Both have sidewalks and pedestrians. You might be seeing Voie Georges Pompidou which is not really for pedestrians and is lower (closer to the river) than Quai du Louvre and Quai Francois Mitterrand but I am not even sure how you would access Voie Georges Pompidou on foot from Pont Neuf. Just walk on Quai Francois Mitterrand until you get to Place du Carrousel.
As JKH says, the highway is under the bridge; you do not cross the highway when going on foot. You will not be alone in taking that route on foot, so just follow the crowds and observe the lights and walk/don't walk signals.
Thanks for the help. (loose use of the term freeway)
It's your California training :-) It's a great walk along the Seine, even better after dark.
And during the day you can go down stairs and walk directly along the concrete bank of the river if you like. I don't like doing that at night as drunks hang out under the bridges, but it is nice during the day if you like.
We made that exact walk and went through the main Pyramid Entrance, there is a separate queue for pass holders to go through security so make sure you look for the museum pass sign and the shorter line!