in route 1 but first you have to ask this question :where is route 1 in soul silver (is me how answerd it)
Route 38
You can find an Arbok in route 3,4,26,27
It is in Route 10, but it is rare to find it.
On route 45.
Swarming on Route 1.
You can find a Rapidash on: Route 22, Route 28, Mt. Silver
You can find a Phanpy in route 45.
You could find Growlithes in Route 48.
She's at the end of route 25
You can find one on Route 38.
find a ralts i think route 34
Houndour can be found in Route 7 in SoulSilver and it can also be found in the Safari Zone.