If you're looking to see groves of redwoods, Muir Woods is the place to go in the Bay Area. It is about 40 minutes north of San Francisco and 20 minutes from the wedding venue. It does get busy, and you'll need to reserve a parking pass in advance, but it is gorgeous and we highly recommend checking it out. You can do the main trail loop which takes less than an hour and is easy to maneuver, or you can spend an entire day here exploring the expansive trails.
The Dipsea Trailhead is across the street from the wedding venue. It has everything: forests, waterfalls, ocean views, etc. There are trails for all skill levels, but the "Dipsea to Steep Ravine" trail is the best. Note that it is 7 miles roundtrip and rated "moderate", so plan accordingly.
Roughly 60 minutes north of San Francisco and Stinson Beach, it goes without saying that spending at least a day in wine country is worth the trek. Our favorite winery is Gloria Ferrer Caves & Vineyards, known for their delicious sparkling wines and gorgeous views. We also love Viansa, Cline and Hanson Distillery for the vodka lovers!