I am so jealous! Growing up in Portland my uncles lived out by the gorge and we had many, many Mothers day breakfasts there. My grandma and sisters b.days are in May so would always do a big family gtg to celebrate it all at once.
There is also a decent outlet mall out that way.
We HAVE to have lunch before you go - I've got a great book called Curious Gorge with a ton of falls you guys could visit.
Remember, this is where we go windsurfing. I've spent a LOT of time at the Gorge