Easy one day drive. Harder to stop at the overlooks driving north as you have to cross traffic twice to get in and out. Doable if during the week I would think. Just be careful
Lewis and Clark RV golf and RV park. Not on the water but there are none on the water that I know of.
Visit the maritime museum. Have fish and chips at the stand across the road from the museum. Visit the sea captains house. Great story and great house. (he was the one who started the pilots industry in the last century to get ships safely across the bar.) Ask at the RV park they are very friendly and helpful. Visit (weather permitting) the bar itself. great views of tankers coming up the river. Visit the Lewis and Clark winter site National Monument. Worth the few hours for sure and if you are into hiking great trails around there. Lots of good places to eat, use the trolley to get around on the waterfront. Take you toad over the bridge - trust ne, you can't miss it. Worth the price of admission
(it's free)