I talked with the portland zoo and they have wheelchairs and scooters
available on a first come first serve basis.  They have lots of
benches and sitting areas.
Wheelchairs $ 6.00  
Electric Scooter  $20.00  
The Portland zoo has it's own max stop (light rail), and they give a
50 cent discount on the tickets if you have a max stub ticket.  I had
the most interest in the zoo but there was also interest in the
gardens.

Chinese garden is ADA accessible, but they do not have wheelchairs or
scooters.  They have many benches and sitting areas.  

Japanese Garden has steeper paths and claim they are not ADA
accessible but they say folks with wheelchairs can make it around if
they have assistance.  Many sitting areas.
here is the access information:
http://www.japanesegarden.com/information/access.shtml

I have heard that of the gardens the Japanese is the most spectacular.
You can take the max and bus  not worry about parking.
http://www.japanesegarden.com/information/location.shtml

So think about what you want to do.  I will probably do the Imax Nile
movie at 1pm on Friday unless there are other that want to do it at
another time.

So let me know if you have strong preferences.  I was at the
Bonneville locks and saw big salmon and many shad making their way up
the ladders. The sea lions were chased off,  multnomah falls and the
drive up the Gorge are spectacular and there are some nice wineries in
the gorge.  You can easily make a day of the gorge.  There would be
more walking but not excessive. -- MZ

Visit my website:
http://www.mzuschlag.com