After some Googling, I stumbled on the solution in this forum thread on the Cocoatech forums. User maaku posted this very handy AppleScript:
on run
tell application "Finder"
activate
set this_folder to (the target of the front window) as alias
close the front window
end tell
tell application "Path Finder"
activate
open this_folder
end tell
end run
Copy and paste that code into Script Editor, then save it as an application (File Format » Application in the Save dialog) in a convenient spot. Then drag the app to the Finder's toolbar or sidebar; I put mine on the toolbar.
Now when I open a folder in the Finder, I can quickly jump to the same folder in Path Finder by simply clicking the icon in the toolbar. The linked forum thread contains a number of additional Path Finder AppleScripts which could be useful, including one that opens two browsing windows.

