The only timeshare remotely close to Redwoods National Park is GEVC at Lighthouse Point south of Mendocino. And it's not very close. The NP is a series of various state and national park sections that stretch for a long distance along Highway 101. The roads up from Hwy 1, where Lighthouse Point is, are slow and windy so it's really not a good base. You would be better off renting a vacation rental in Eureka.
There are timeshares in Napa or Monterey area that you can visit various Redwood groves from. However, if you want to export the National Park sites, you should look at non-timeshare options.
Sue