Thanks to all of you! It sounds like we need to spend 2 weeks and are going to gain plenty of weight! @walkinghome thank you for linking the previous thread. I searched for it yesterday and apparently did not put the correct key words.
I make sure this gets into every Seattle thread, and since this is cc:
Get lunch (and paddle boards/kyacks for lake Union area) at Agua Fresca on the waterfront by UW. Great food, great views, your lunch table neighbor might be a UW professor.
Second what BB says about the Seattle City Pass, lots of bang for the buck. You have lots of good advice here. The EMP is unlike any other museum.
Mt. St. Helens is an exceptionally long day, 100 miles south on I-5 then another 60 miles on a two-lane mountain road. I was fishing last weekend near there and the danged salmon kept jumping and scaring the bejeesuz out of me; they are definitely in the rivers now. Definitely do Mt. Rainier if you get a clear day - go in the east entrance and up to Sunrise, then back down to the other entrance. See the big trees, a short hike in to Grove of the Patriarchs and a bouncy bridge across the gin-clear Ohanapecosh River. They have taken some of the displays out of the museum at Paradise to make room for a cafeteria, not an improvement.
Market Street in downtown Kirkland is worth a few hours. I usually eat cheap while I am there since I am not that impressed by the more expensive restaurants.
Another vote against eating at Snoqualmie Falls. Depending on how your mother feels, there is a 1/2 mile downhill hike to the base of the falls, but then you have to turn around and hike back up.
Also skip MOD pizza, OK but not worth missing the other places for it. No to the University Village shopping area unless you really want to see an Amazon brick-and-mortar store.
For others looking at visiting the area, downtown Redmond is really being developed and is becoming more lively. It also has an express bus (#545) into downtown Seattle.
Another vote for the Chihuly museum. I finally went and loved it. I also finally went to the new Museum of History and Industry on South Lake Union. The old version was a favorite as a kid. I loved the new one and think they did a great job with the historical displays and all the hi lights of the city. The views are excellent as well and there is a nice waterfront view. I would not miss it.
If you park by the sculpture park and walk through to the bottom there is a little beach there at the south end of Myrtle Edwards Park. The views are lovely from the water.
Yay, good to see you, @saintfan! 
Absolutely second the suggestion of MOHAI.
Someone suggested the Arboretum for a nice peaceful walk. There is a beautiful Japanese Garden nearby - I highly recommend it.
So happy to see Saintfan!!
I wouldn’t suggest seeing the University Village shopping center, or UW’s campus,except for it was kinda fun seeing a brick and mortar Amazon store at the U Village and it’s where this restaurant is located: Din Tai Fung https://www.yelp.com/biz/din-tai-fung-seattle. Also, having read and loved, “The Boys on the Boat”, it was cool walking around the University of Washington’s campus.
We went to the sculpture garden early one morning, and while it was mildly interesting we made two mistakes - we went went the adjoining museum wasn’t open and we went went it was cool and rainy. To me, it was just not worth a special trip, but okay if it was on the way to someplace.
I think the four things I liked best were 1) Pike Market (I could people watch all day there), 2)The Sky View Observatory http://www.skyviewobservatory.com/ 3) The Museum of History and Industry and 4) The Chihuly museum.
And those are four things that I would happily do again. There were several other things that were can’t miss too, like the ferry, the underground tour, yes, the gum wall, the huge Starbucks roasting store and taking all kinds of public transportation. On the other thread I mentioned the hotel we stayed in. It was comparable to the airbnb’s we looked at: https://www.tripadvisor.com/Hotel_Review-g60878-d100544-Reviews-Moore_Hotel-Seattle_Washington.html
There are a lot of great restaurants in Seattle, and a lot of them are somewhat hard to get into. I recommend downloading the OpenTable app for your phone and using that to help you figure out dinner plans – sometimes even lunch as well.
There is also a Molly Moons ice cream place at the UW Village. 
I have been on hiatus but I think I’ll step back in. waving I had forgotten my password.