Yes, probate is the only way to transfer that real property. Just know that probate is not necessarily something to be worried about here in Washington. The process can actually be fairly simple, straightforward, and inexpensive. In fact, all that paperwork (there shouldn’t be tons of it) and process are not a big deal, especially if you hire an experienced lawyer to help you out.
There may be some shortcuts you can take too. For example, you may not need to publish a notice to creditors (although the benefit and low cost of doing so often outweigh skipping it).