By road, you can reach the Bulkley coming either from the West or from the East. Going there from the West would be by taking the ferry to Prince Rupert from Port Hardy on Vancouver Island. Going there from the East you would drive towards Smithers from Prince George. If you choose, you can also fly directly to Smithers from several airports.
Accommodation is to be found in Houston, Smithers, and New Hazelton. Moreover, there are some possibilities to rent private cabins or rooms along the road outside of town.
The stream gets his name in the town of Houston from a small tributary running into the Morice. Technically, the source of the stream is really the Morice. As far as I know, not even the locals know why the river downstream from Houston is called Bulkley instead of Morice.
The stretch open to fishing starts in Houston and ends in Hazelton. In between there's 136 kms of highway, and that tells you that the stretch is considerably longer. Using flies there is not too complicated, the work is in finding access to some promising spots. Well known spots are the Quick Bridge and some others around Telkwa, Smithers, and Trout Creek. To find other good spots, you'll have to invest some searching to find access by road or by foot. Once you find a good run, you may hook several fish a day. I must admit, though, that I've never caught a steelhead above 90 cms in the Bulkley.
Without doubt, the capital of the Bulkley, if any, is Smithers. It is situated right in the middle between the towns of Hazelton and Houston, so Smithers should be your best bet for accommodation. Within 20 km from Smithers you will find more promising spots than can be fished in a three week vacation - if you could get three weeks off in the first place. Furthermore, in Smithers you can obtain anything you need for your vacation or even for life in general. Doctors, large food markets, stores for beverages, clothing, or hardware and good local restaurants and cafés make for a safe and pleasant stay, Finally, there´s the Hudson Bay Mountain Ski Area only about a 20 km drive from Smithers. It has many different slopes. The main season is of course winter, but it is always worth a stop-over, even in summer.
Your questions concerning fish and stream should best be addressed to Oscar´s Source for Sports. The shop has a very good department for fisherman and both the owner as well as the sales people know their river well. Almost anywhere where anglers fish for steelhead, the only way used is fishing on a downstream swing, for streamers, dries or nymphs alike. Almost no one tries fishing nymphs dead drift, the way we prefer.