You musn't over walk your pup, it can and does cause bone growth damage, so be very careful. Pups need short bursts of energy and then rest, not continual walking. I've always walked my pups with their mum once inoculations are finished, especially for the first couple of weeks, the pup does not leave it's mum's side and she helps to give her pup confidence and also a pup will click very quickly that they are supposed to toilet on the walks too after watching what mum does, after the allocated time, I will then pick up my pup and pop it in my carry pouch for the rest of the walk, if I stop for a while I will let the pup out to play.
As the pup gets older we do much more one to one that is something that you will need to do, also as a pup gets older it will not wish to be in the carry pouch but out and running with the other dogs, you'll end up with a struggling dog so you will need to do one to one instead, but certainly for the first couple of weeks it will do your pup good to walk with it's mum for some of the way. In no way should you allow your pup to walk the same as your adult Westie, not until much older.