Can I go to Muir Woods today?

Yes, if you plan it. The park is open every day of the year unless they close it for a storm or a fire. If you're driving you need a parking reservation from GoMuirWoods. They do not sell them at the gate. There's no cell at the booth, and they will turn you around. Busy day: take the shuttle. Check NPS this morning before you leave.
NPS hoursKnow before you goGoMuirWoods
Muir Woods
Parking reservation
If you drive, you need a pass from GoMuirWoods.com. None sold on site. No cell at the gate. Without a pass, you get turned away.
Muir Woods
Check NPS this morning
Open 365 days except emergency closures. This page does not flip Open/Closed by hand. NPS is the source.
Marin
Shuttle
The sane move on a weekend or a holiday. Parking fills. The shuttle does not.
Muir Woods
Pets
Dogs are not allowed in the woods. Leave them home, or pick another trail.
Marin
More walks
Tennessee Valley, East Peak, Cataract. The hikes guide.
Mill Valley
Equator Coffees
Downtown, across from the Depot. Coffee before you hit the freeway.
Mill Valley
Buckeye Roadhouse
On 101 on the way out. The roadhouse. Sit down if you have it in you.

Mill Valley
Tartine
Strawberry Village. Morning bun, country loaf, a patio. 8 to 4.

Mill Valley
Cholita Linda
Across from Tartine. Tacos after the woods.
Mill Valley
More Mill Valley eat
The rest of the Mill Valley list. Piazza d Angelo and Piatti are downtown too.