Downtown Portland is a 45-minute local bus ride (Tri-Met #12) from the Airport (privately--run express buses are available at higher costs)
Downtown Portland features "Fareless Square", where all bus and light rail service is free. In addition, 5th and 6th Streets are bus-only streets (the Transit Mall). Many people get around Downtown Portland simply by hopping on a bus, riding a few blocks, then alighting.
The light rail is called MAX, and runs between Portland and Gresham, to the east. Most MAX service is provided in reserved right-of-ways along streets; there is a short section near the freeway where the trains can get up to speed. Construction has started on a MAX line going west of Portland, and a north-south line is being planned.
Amtrak and Greyhound are adjacent to each other, in the north end of Downtown Portland, and are within Fareless Square.
Downtown Seattle also features a special tunnel for buses, with five stations. Special hybrid (diesel and electric) buses are used, with the buses using electric power in the tunnel. Within the tunnel, passengers are encouraged to board the buses through any bus door, speeding up service. The tunnel is not used after 7 pm, or on Sundays.
A streetcar line, using five antique trams (from Melbourne,Australia) operates between Jackson Street (near Amtrak and the bus tunnel) and the waterfront. And, the monorail between downtown (Westlake Station) and Seattle Center has been operating since the World's Fair in 1962.
Seattle Metro covers most of King County, including express and local lines to Sea-Tac airport, the University of Washington, and other points of interest.
Other transit operators in the Puget Sound area include:
Fares (CDN$1.50, about US$1.11) apply to all of the above mentioned modes. An all-day pass is available for CDN$4.25 (US$3.15)
Ferry service is also operated between Vancouver (actually, Tsawwasen) and Victoria (Sidney, BC), although local transit connections can be complex. It is probably better to use Pacific Coach Lines, a private bus company that rolls right onto the ferry. Pacific Coach Lines, along with Greyhound and most other intercity bus services, operates from the Pacific Central rail station. Both Amtrak and VIA Rail use this station, and the Skytrain stops nearby.
In general, it was easy to get to most destinations in each of these cities by public transportation. The fare free zones in Portland and Seattle, as well as the Seattle bus tunnel, were most useful. I also liked having the intercity bus and rail carriers all in one place, as is done in Portland and Vancouver.
Seattle seemed to have the best airport connections, with Metro buses (including a frequent express #194 to Downtown Seattle). Portland's Tri-Met bus serves the terminals as well, but is a rather slow local. Vancouver's BC Transit requires a bus-to-bus transfer just outside of the airport. (There was a transit bus marked "YVR" and "Airporter" operating around downtown--I have no idea what the fare is)
Local transit to Bay Area airports varies considerably. Oakland Airport is served primarily by AC #58 to Oakland, and the Air-Bart Shuttle. Both serve Coliseum BART, but AC Transit is cheaper ($1.25 vs. $2.50?)
San Francisco Int'l has several local bus routes serving it. Samtrans #7F to Downtown S.F. is the fastest, but does not allow luggage (a small bag is ok). #7B is slower, but allows luggage. #3X serves the Daly City BART station.
San Jose Int'l has the least convenient transit service. A free shuttle connects the terminals with the light rail during the week. On weekends, the only service between San Jose and the Airport is SCCTA #65, lightly used and rather infrequent . . .
Portland, Seattle and during rush hours only, Vancouver, have zone fares; the service area is divided into several zones, with additional fare required for trips crossing zone lines.
In Seattle, on buses leaving downtown, one pays when *leaving* the bus.