BTW, this might also be worth exploring, for a scenario involving large-scale Imperial Chinese colonization of the West Coast of North America:
This long and rich vein of jade deposits, aka as 'The Nephrite Jade Road', comprise the largest, and some of the best quality, deposits of nephrite jade in the world. And most of this is located in the watershed of the Fraser River; the longest river within British Columbia, Canada, which rises at Fraser Pass near Blackrock Mountain in the Rocky Mountains and flows for 1,375km into the Strait of Georgia, just south of the City of Vancouver. There are several islands in the Fraser River Delta, with the largest of these, Lulu Island, being divided between the cities of Richmond and New Westminster. So I'd argue that Greater Vancouver would actually be a lot more likely to be a major port city in this scenario than IOTL, with controlling the Strait of Georgia being a higher priority for the Chinese colonials than controlling the Puget Sound- though the Puget Sound region would probably also see large-scale settlement, predominantly for agricultural production in the early stages.
In California itself, the largest masses of jadeite can be found in the Saint Lucia Mountains, going inland from the aptly named Jade Cove on the Central Coast (but isn't mined commercially, since it's a strict conservation area covered by the Big Sur Local Coastal Plan. This is mostly concentrated in the county of San Benito, with the San Benito Valley accessible to both Monterey Bay (via the Pajara River, making the site of OTL's Monterey another good candidate) and San Francisco Bay. And some of the largest nephrite (as opposed to jadeite) jade deposits can be found across Wyoming, but predominantly in the Granite Mountains region, with Wyoming apple green nephrite jade renowned as some of the finest nephrite jade in the world.
To the West of the Great Continental Divide, this is accessible from the sea via the Green River and Snake River, which respectively form the largest tributaries of the Colorado River (which flows into the Gulf of California between Baja California and Sonora) and Columbia River (which forms most of the boundary between the US States of Washington and Oregon, with the port city of Astoria situated on its southern shore close to the mouth of the river- which is also the largest river by discharge flowing into the Pacific from the Americas, and prior to being dammed, was one of the 10 largest in the world by outflow, on a par with the Yangtze River in China).
So this provides a significant boost to Astoria's credentials; or perhaps, given the greater prioritization on colonization north of the Columbia River, in Western Washington, another city on the opposite northern bank of the Columbia River instead? If you want a candidate out of center-field, how about Cathlamet, in Wahkiakum County- which was the largest village of the Native Columbia River Indians west of the Cascade Mountains, with a larger reported population at first contact than it has today, and the home of the now effectively extinct Kathlamet people? Sure, it may be the second-least populous county in Washington today IOTL, with fewer than 4,000 people; but perhaps ITTL, with the jade deposits to the north (and rich silver deposits further inland, found in abundance in the interiors of Washington and British Columbia, as well as in Idaho and Nevada) prized more by the Chinese than the gold deposits to the south, things might be very different in that regard?
So, looking at Chinese colonization of the interior; I'd argue that the Columbia River Basin would be the likeliest candidate to be the center of Imperial Chinese population in this scenario, in a manner akin to the Yangtze, Yellow and Pearl River Basins back in China (with the Yellow River in particular serving as a fairly good analogy, with the northern section of the Columbia River comparable to the Upper Ordos). And its valleys are definitely the easiest and clearest path to facilitate Chinese colonization of the inland Northwest, all the way to the Rocky Mountains.
The Spokane River Valley's also definitely worth a mention, with the Coeur d'Alene Mining District in the Idaho Panhandle also known as 'Silver Valley' for a reason. IOTL, the Spokane–Coeur d'Alene combined metropolitan area's the economic and cultural center of the Inland Northwest; you'd imagine that it would be ITTL as well. And further downstream, the Cowlitz, Lewis, Willamette, Deschutes (originally known by the Native American name Towarnehiooks), John Day (originally known as the Mah-Hah by the native Cayuse people) and Yakimi River Valleys could also all well host Tier 2/3 cities.