Best Route

I5N to 18E to I90E.

Shortest mountain route. Should be a breeze in Sept. Rain most likely, but no snow probably.

When you get to Yakima, note that the Golden Apples the Yakima valley is famous for are soon to be harvested and you should buy an entire apple box full. They are so fresh, you are still eating crisp apples weeks later.

gafidler wrote:
leaving Ft Lewis, WA heading towards Yakima WA in Sept. which routes to take with a 39 ft MH and CRV toad ? 90 / 12/ 410. thanks for your help.

You should edit your original post to change the title of your thread. To be helpful, your title should include the "from" and "to" locations:

Best route from (place) to (place)

410 is the most scenic, with great views of Mt Rainier - but it would also be the most challenging. It's pass is one of the last to be cleared of snow in the spring (June).

12 is easier, and starting in the south Sound makes it more attractive. But there are some construction projects this summer.

The 18/80/82 is all divided highway, and faster.