What facilities should I look at.

There are organizations that may help you narrow down your choices. Your local Area Agency on Aging and A Place For Mom are two of them. I looked at places that were strictly Memory Care and some that were both Assisted Living & Memory Care. I had a similar experience to @blacksparky where I looked within a certain radius and chose one that was not the newest but it had a cozy feeling to it, and a beautiful outside walking area (it was memory care only facility). Besides the obvious questions about staffing and their methods of care, think about what would make your wife happy - would she like to be able to go outside (a big plus for my DH)? Would she like a busy activity schedule? Would she like a big fancy room?

There are many people on here who have posted also about care homes, which are smaller facilities with a better staff to resident ratio.
I encourage you to start early to research and tour facilities, long before you need it, because it may need to be your Plan B in case something happens to you.