Hi, noobfisher.
Barfishing is simply a type of stillfishing in the Fraser river. It is the traditional way of catching Salmon in the Fraser. The other method is bottom bouncing, but I'm not going to elaborate on that (don't bother asking). Bar fishing is very simple, you use Salmon roe as a bait, and a large lead weight to anchor your line. A bar rig may be used in the Fraser, which is simply a type of tandem hook setup.You simply cast your baited line out, and place your rod in a special rod holder and wait for a fish to bite. Usually a lawn chair and holder are brought along to make things more comfortable. The holder and a chair are very bulky and wouldn't be convenient to haul around on a bus. They are not essential, but do much improve the bar fishing experience.
If you are interested in barfishing fishing the Fraser, I would suggest getting a map of the various bar locations from a tackle store. Some locations can be very snaggy. You could end up loosing a lot of gear, an with the the price of lead these days, could get expensive. Salmon roe is also pricey to buy, if you don't have a ready source. Chum Salmon roe is the prefered bait, dog roe as it's known is usually sold at Berry's Bait in Ricmond.
I think you'd be better to try and find a partner with a vehicle if you'd like to try barfishing. You would have a hard time hauling a chair, holder, and cooler around on public transport. A cooler is required even if you don't catch any fish because you must keep the roe cold.
Annacis Island is a traditional bar fishing location, but I couldn't tell you exacly where the bars are. That's where the map comes in handy, call a few tackle stores and see if they have one in stock. It's a cheap investment and will save a lot of frustration trying to figure out the bar locations.
Regarding Stanley Park, I'm sure you'd pick up the odd rockfish off the seawall. I've heard that it's not exactly a convenient place to try and fish though. There's thousands of people out on the seawall every day, so you better watch your back cast.
Good luck to you.