For the Oregon Trail:
(Source:
https://trimet.org/publicart/pdf/greenline-i205-cultural-history.pdf , page 10)
"Settlers had two main paths to reach Oregon City, where they rested, restocked
and registered their Donation Land Claims (DLC). Until 1845, the main route
was overland to The Dalles, by water down the Columbia River and then up the
Willamette. After 1845, Sam Barlow’s road offered an overland alternative south
of Mount Hood, albeit a toll road. The Foster homestead, after which Foster
Road is named, was the first sign of civilization and the last stop before Oregon
City. Foster Road itself was an extension of the Barlow Road that led straight
towards Portland, rather than southward to Oregon City. Another path may have
developed down the same approximate path of I-205 and 82nd Avenue, from
the Sandy River to Powell Valley Road and then south."
For us, that would be along I-84 west of US 730, then I-205, OR 213 across the railroad tracks, then south on Washington St to the End of the Oregon Trail Interpretive Center. (I recall seeing Oregon Trail signage on southbound I-205 south of I-84 back in the '90s and aughts. I'll make a field check tomorrow).
Technically speaking, I-84 to OR 99E, and OR 99E to Oregon City should also be included, but there's never been any signage that I know of.
From my notes in the OR route fixes to match the Oregon Trail and Barlow Road:
Barlow Trail: Recenter western point with OR 211 to OR 224's location. Point needed with Eagle Creek Road needed (for Clinching via TriMet's line 30 Estacada).
Note: Suggested point with Barton County Park on Baker's Ferry Road just south of OR 224.
Extend north from its terminus at Abernethy/Washington north just a bit to the Interpretive Center (EndORTrl?).
Barlow Trail apparently has two points at the US 26/OR 35 interchange, one for each route. That should be collapsed into one point.
Barlow Trail_Wasco will need points at both intersections with Clark Street -- north of OR 206, and the one with OR 206.
Foster Road: No signage on the ground, but per TriMet, it looks like it was part of the Barlow Road from Damascus at OR 212 into Portland (Powell Blvd/US 26). No description given, but the connection to the rest of the Barlow Trail would be via the 212, 232nd Ave, and the 224 to Baker's Ferry Rd.
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Lewis and Clark Trail: Though I doubt it's signed in the field, the entirety of US 30Y (and NE 23th Ave) should be verified if it's officially part of the L&C Trail, as well as I-84 from there to US 730.
Also, for the Washington side, I think it goes north along the Astoria-Megler Bridge, not west to WA 100.
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Ok, now I'm curious. What was the Applegate Trail's routing? I remember seeing shields for it along OR 238 near Ruch as a kid.