We sat there about 25 minutes, deciding which MAX to catch, the Red or the Blue. Mama wanted to go as far as possible, so we decided to go to the western end of the Blue Line, out in Washington County, to Hillsboro.

Here's Mama! Note her useful and beautiful carved cane and my ever-present rolling black bag.
We rode from a few blocks west of the Willamette River to the middle of suburban Hillsboro, around an 18 mile ride. When we weren't in the tunnel that goes through the West Hills, Mama sat like this the whole way.

In Hillsboro, when the MAX car announced end of the line, we got off and boarded the waiting Blue Line to Gresham, as far east as the line goes. Mama announced that we'd get off at PGE Park and not go all the way to Gresham--she felt like that would be enough for one day. So we did get off, and then walked over a block and caught a 15 bus home. All told, we had an enjoyable meal and over three hours entertainment, for under $35, including the brunch and tip. Mama wants to go again, and so do I. Next time, we'll ride east and make a bus connection, too, maybe heading north, maybe south. Or we'll ride the Red Line to the airport. It's so great that we have options.
UPDATED TO ADD: The MAX is Portland's light rail. From TriMet dot org, TriMet's MAX Light Rail system connects Portland, Gresham, Beaverton, Hillsboro and the Portland Airport. Trains run every 5-15 minutes roughly between 4:30 a.m. and midnight.