The parade is about 16 minutes end-to-end.
It starts at the Fire Station on Main Street and "rounds the Hub" and then goes thru the Frontierland entrance and all the way back and out of the park near Splash Mountain area.
It runs exactly the same speed every time and reaches near the Country Bears Theater 24 minutes after it starts at Main Street (7pm parade-start at Main St., 7:24pm front of parade arrives at Country Bears area.)
So, if you want to shop, you need to figure WHERE you'll WATCH, and WHERE you'll SHOP.
Assuming a 7pm start:
The parade is "over" (concluded) at the Main Street Railroad Station by 7:17pm.
It would be possible to take the train to Frontierland Station and "BEAT" the beginning of the same parade before it gets to (that end of) Frontierland.
You COULD watch it AGAIN
OR...
Ride SPLASH and BTM over and over as everyone ELSE is watching the parade YOU already SAW at Main Street.
I can tell this isn't anything new to you. I watched this awesome parade during one of the first years it debuted in 1995, but could not remember its length, nor did I think about its complete route, so your suggestions are very interesting.