You have to go through the Ice Path. It is located east of Mahogany Town. The slick ice makes for a tricky puzzle, along with the boulder puzzle later in the Ice Path.
no you have to beat the gym leader
Yes, Clair the Gym Leader of Blackthorn City and a Dragon-type specialist is the 8th and last Johto Gym Leader in Pokémon HeartGold and in your Gym match against her she will use two Dragonair both of which are at Level 38 additionally she'll use a Level 41 Kingdra and a Level 38 Gyarados and after receiving her Rising Badge after a quest in the Dragon's Den you will be able to control all Pokémon, you will be given TM59 and you will also be able to have Pokémon use the HM Waterfall outside of battle.
Train your Bayleaf.
Olivine City
After you beat Falkner, he is always in the gym.
You need to have the HM whirlpool which I belive you get from the 7th or 8th gym leader in Johto
beat the last gym leader on soul silver in johto
defeat all the gym leaders in johto and kanto hope this helps
you have to use the HM surf and surf behind the gym and go in the cave. go to the other side of the dragon temple and go in. awnser the old man's questions and the gym leader will come in and give you the badge. This is to get the 8th Johto gym badge. To get the Kanto one search: how do you get to the 8th Kanto gym badge
move to the 8th gym
cindber island
you get it once you have all the johto gym badges then go to Professor Elm and he will give it to you
for the johto region, it's in blackthorn city. for kanto, it's in viridian city after you beat the cinnabar gym.
In Blckthorn City
Yes.
in the ice cave before the 8th gym
You can access Cerulean Cave in SoulSilver after you get all 16 gym badges (Johto and Kanto).