Please help us find some surf/turf options for our first anniversary trip.

Timing:
September 17 through ?

Ideal setting:
Someplace with cool weather where we could hike during the day, walk on the beach at dusk, and light a fire in our room/cabin at night.

Does such a place exist?

Please tell me straight out if you think I'm smoking crack!

Thanks.

Lake Tahoe, North end of the Lake, Incline Village maybe. You have a beach with beautiful turqoise water, mountains to hike in and quiet. If you want night life however, you are better off in the south end of the lake.
Tahoe is gorgeous and in my opinion has what you are asking for.

That time of year is beautiful on parts of the central/northern California coast. The summer fog pattern starts to give way to sunny and warm days and cool evenings. One of my favorite spots is Sea Ranch on the Sonoma coast just south of Gualala and north of Jennner. We rent a house there almost every year. Most have hot tubs and fireplaces. The Sea Ranch Lodge is a nice place to stay if a house rental is not your cup of tea. Great hiking in the hills and along the coast, beautiful, long expanses of beach for walking and hand holding, and great sunsets. Late September and early October weather is usually lovely.

-Bill

Mendocino area along Northern California coast. Gorgeous coastal views and nearby state parks with hiking trails.

Malibu.

Why not Hawaii?

Both Maui and Big Island have exactly what you described.

The Northern California coast suggestions you've received already are terrific. Here's another:

Visit the redwoods in Muir Woods just 12 miles north of SF's Golden Gate Bridge. There's hiking trails there as well as at nearby Mount Tamalpais. Then take the scenic drive down to Muir Beach or Stinson Beach, one of my favorites in CA.

A few miles further north, you could also visit Point Reyes National Seashore with its quaint lodgings at Olema and Inverness.

Costa Rica?

Big Sur...