Asking for Trip Suggestion over Labor's Day Weekend

Come to Arizona! You can take a train up to see the Grand Canyon and stay at the historic lodge up there, take a hike or mule ride into the canyon, go fishing if you are into that. Then you can spend a day or two in Sedona- Slide Rock would be a BLAST with your twins, then maybe hit the Children's Museum, Science Center, and/or Phoenix Zoo in Phoenix before you leave.

ETA: Phoenix is hot, Northern AZ, where the Grand Canyon is, will be much less so! Look at temps around Flagstaff to get an idea.

I would take the Coast Starlight train up the coast to Seattle. Great city.
Would be great for a long weekend. Your boys are a perfect age for a train trip. You would need to get a room for overnight. Although coach is not bad. Kids sleep great on the train. Think they are at least 1/2 price if not less.

San Francisco, stopping at the Monterrey Bay Aquarium along the way

Pop into an AAA office and see what offerings they have for the 4 of you.

I would not recommend Arizona, as it will be uber hot.

There are lots of last minute cheap cruises out of Long Beach, that go to the Catalina Islands and down to Ensenada, or somewhere in northern Mexico.

Your past vacations seem full of amusement parks and activity. So perhaps a back to nature trip might be in order. Check out the cottage options on California's State Park website. I love Crystal Cove!!!!!

A trip to Catalina might be nice, if you can find lodging there on such short notice. It's relaxing, lots of places to walk, little golf-cart-type cars, canoes, paddle boats, swimming/wading, and cool weather. Our daughters were a little older when we went, but they loved it, and I think kids your age would probably enjoy it, too.

You could go to Palm Springs. It is hot, but we love it. We swim in the early
morning, go inside during the peak sun from 12-4. We go to the movies or there is a wonderful children's museum. My kids love to swim. There are some wonderful hotels there that are time shares and they rent by the night. Some we even have kids crafts and activities during the day.
You could go to Big Bear or Lake Arrowhead.
Solvang and Santa Barbara. Santa Barbara has a cute zoo and the mission is there and Solvang is a cute town to wonder around.
San Luis Obispo. Monterey Carmel.Pismo Beach And if you want to go further up, San Francisco where there are numerous things to do. We are so fortunate to have one of the most amazing coast lines.
Whatever you decide have an amazing time. I have 6 year old twins and we love to travel.
T.