Oregon Trail/California Trail/Pony Express in Kansas:
All three enter from Nebraska on
K-148 and turn east on US 36.
At US 77, the Oregon Trail and California Trail turn right, while the Pony Express and a spur of the California Trail continue straight.
The Oregon and California Trails go east on
K-9, south on
K-99, east on
US 24, south from
Rossville, east on I-70, east on
US 40 and old US 40 into Lawrence, south on
US 59, east on
old K-10 and K-10, then probably east and north on I-435 (definitely on I-435
in Missouri), but I don't know how far (probably at least to US 24 east).
The Pony Express and California Trail spur use US 36 into Missouri, where they use
I-29 Bus north to at least
Mitchell Street.
Wyoming
also signs them, but I haven't looked in detail yet.