Grand canyon for maybe 3 nights

The Grand Canyon is beautiful in the winter, but 3 days is probably
more than you'll need unless you plan to hike into the Canyon. Keep in
mind that the trails will probably be cold and snowy. Some folks enjoy
winter hiking; others don't.

About 10 days in LA/Anaheim

Your kids will love Disneyland, but you might want to spend some of
that time in San Francisco instead of LA. Most folks consider SF a much
better vacation city than LA.

There are also some beautiful areas near San Francisco, such as Muir
Woods (redwoods), Napa Valley (wineries), and to the south there's the
Monterey Pennensula and the "17 Mile Drive" (magnificent ocean
scenery), Point Lobos park (hiking trails overlooking the ocean), etc.

Jim