to get to island 2 you have to talk to bill and his friend. After you do that you have to go back tothe sailor in front of the ship and talk to him he will ask you where you want to go and go to 2 island I HOPE IT HELPS!!!
About 2
You can't get to Four Island in Pokemon Red Version.
There is no such island in Pokémon Red.
2 island
One island Pokemon centre after you defeat elite four and the 2 rockets at the volcano and find the gem.
Ofcoure..But You Will Need Ruby and Saphire Stones Form Island 1 2 or 3...
its on cinibar island just like red blue and yellow
you cant
there is no mushroom island.
island 4
a valley on six island
On Cinnabar Island.