I do not know what condition your grandparent are in. It does make a difference. I am sure that they would want to be together, or at least in the same building if one of them needs to move to a nursing home environment. There are only two facilities in the area that can really accomplish this, The Mount and The Kenney. Check the fee structure at both, they are different. Both are sponsered by religous organizations (this is an attraction for us.)
I currently have a parent at Merrill Gardens in the Admiral district. It is an assisted living facility, but they have a higher level of care than other assisted living facilities in the area. It is also smaller and less confusing than the Mount. I have been pleased.
They have activities, a beauty shop,a wide range of care offered, a RN on site Mon.- Fri, and a 'concierge' service which is really nice. This is a person that can do anything you would do and is really helpful if you cannot be there to assist. It does cost, but the charge is reasonable (take parents to store, out to dinner, pick up odd items they need, sew a button on etc.) We have had a pleasant experience there. They try hard to keep their residents as long as possible and even have hospice patients, but if you really need nursing care, or really need memory care, they cannot do this.
You can also look up on the DSHS site for adult family homes. These can be really great - but you have to look at each one. This type of facility bridges the space between nursing homes and assisted living facilities. (When you are too well for a nursing home but need more care than you get in an assisted living facility.) They are houses with a couple of caregivers for a smaller number of people living there. Usually they are in 3 bedroom homes with 1 - 2 people per bedroom and a home like atmosphere. They can cook more to your parents liking and the care can be more intensive. If you can find one that both parents can be in together it might be a nice fit. I had a great experience at the Arbor Heights Adult Family home. While a parent was there I utilized 'The Mounts' Adult Family Day program and I have nothing but good things to report about that too. They usually do not have much in the way of activities, but there is a time when that is ok.
Please take the time to visit each place. My conclusion is that there isn't a 'perfect' place, but there are places that really try to do the best they can given the circumstances. To quote Dorothy, "there is no place like home". I wish you the best during this rather stressful time.