In Johto:
Violet City
Azalea Town
Goldenrod City
Ecruteak City
Cianwood City
Olivine City
Mahogany Town
Blackthorn City
In Kanto:
Pewter City
Cerulean City
Vermilion City
Celadon City
Fuchsia City
Saffron City
Seafoam/ Cinnabar Islands
Viridian City
no
You need to complete the gyms and the elite four in johto first
yes
You get rock climb at the one of the gyms
The answer is... No there are no and i repeat NO hidden gyms on Pokemon soulsilver (but there are more gyms in kanto which you can get to by the boat pass from prof elm after you defeat the champion)
You have to beat all 16 gyms.
you need to beat all gyms, the E4 twice and red.
Go to Kanto, beat the gyms, go to Mt Silver and beat Red.
there is another region in the game that is red version and you have to beat all the gyms.
yes as meny times as you want also you can battle gyms
You have to beat all 16 Kanto gyms, then talk to professor oak.
I use to play it so i think your supposed to go back in the gym