Hi, I am planning on visiting my man next year and as I wont be staying too far from Sequoia national park in nrthern CA I was wondering if anyone has been there, what they thought, any tips/ hints/ things to do there etc... thanks

Uhm- Sequoia is not in Northern California- It's in the southern end of the Sierra Nevada range, near Visalia.
That said- the Wikipedia page for the park is pretty good (http://en.wikipedia.org/wiki/Sequoia_National_Park)

Redwood National Park (http://en.wikipedia.org/wiki/Redwood_National_and_State_Parks) IS in Northern California, and is my "home turf", let me know if that's the area you mean because I can offer all sorts of info you won't find in the brochures;)

yeah the one near visalia is the one i mean.