It's a total con-job. Cabbies gather at the Keelung bus stop where tourists wait for the bus that goes to Jinguashi and Jiufen, tempting you with stupid short trips around that area, to see the Jinguashi, a really lame castle (which looks like an abandoned fort) and some dirty seawater. Do not fall for their courtesy and kindness. They will dupe you into sharing their cab with some locals to reduce your cost, and then trap you into taking their tours once you are on board. It's not like you can just get off in the middle of nowhere.
Instead, like what
-Ade- said in his blog, take the 1013 "Jinguashih" bus just in front of Zen Shyang Clinic, just about below the pedestrian bridge. If you are coming from Yehliu like I was, it is the first stop after you see the Keelung waterfront. This is the bus schedule for bus 1013, which also goes to Jiufen.
Personally, I think you can skip Jinguashi, and all that crap, if you want to just see the old tourist trap, Jiufen.
Mr B's expression describes what I feel about Jinguashi
At Jiufen, there are three things you must do:
1. the confectionery shop just next to the bus stop. They make Sun Cookies 太阳饼 with a light buttery flavour, totally delicious. Never buy the ready made crap (made with shortening) when you can buy them freshly baked with butter. However they only take pre-orders for 太阳饼, though you can buy the local Pineapple cakes 凤梨酥 instead (this is popular with Hongkong tourists). Don't worry, you don't have to travel to Jiufen to order from them, you can order from their shop at Taipei Main Station. To get them at their freshest （they last 2 weeks) order them to be delivered at the Main Station shop the day you are leaving (as they deliver around 10am from the Jiufen shop). Here is the shop's signboard if you are looking for it at Taipei Main Station (it's one of the tiny shops in the middle block of the arcade).
2. Try Lai Ah Poh's Dumplings 阿婆粉圆. How do I describe it? They sell flour dumplings of pumpkin, yam, green tea, or sweet potato flavour, served cold or hot in a sweet soup containing red, green and haricot beans. Unique flavours in every bite. They use cute recycled school chairs for seats and a giant marble slab for a table.
3. Admire the old street and the surrounding countryside.
