If you are planning on spending most of your time on the east side, then I would suggest staying in Troutdale or Hood River. If not that, then I would definitely take Portland over Vancouver.

The Edgefield in Troutdale is a fun place to stay - there is a brewpub and winery and a movie theatre - beautiful grounds to walk around on-live entertainment at times and last time I was there they had outdoor barbeque cooking fresh salmon.
But we forewarned that all rooms do not have private bathrooms -
However it is a very fun place to
stay

http://www.mcmenamins.com/index.php?loc=3