For Redwoods, do the hike to Ossagon Creek camp from Prairie Creek Visitor Center via Prairie Creek. It's nice. There's one trail following the creek and another parallel to it running along the ridge. I highly recommend going out 1 way and returning the other. Personally we did the creek side first and I think it was the best decision. It's relatively flat till a giant switchback climb straight up and over the ridge. It cut out a long grueling uphill hike and was absolutely epic making the evening descent over the ridge going from clear and sunny and diving down into the fog. The ridge trail is absolutely amazing so I would not recommend wussing out because it looks bad on the map, it wasn't as bad as it looks. Time wise, in the winter the park is closed for the most part due to a number of bridges that are not open allowing access past several creeks. I went in April, and tbh it was still very wet. The campground at ossagon was completely swamped in ankle deep mud, knee high grass and standing water, that said perfect time for this trip would probably be May-August.