Where is the best place for a secret hideout on pokemon emrarald?

go to fallarbor town then keep going left till you see a man standing with his poochyena then start going down till you get to a Brig and then you will see a man with a red and whight hat standing in it stand next to him and you will see a island use surf to get over to it now you will see a pine tree go in front of it and use secret power then go up in it and it has a walk way tow rooms and 66 of you can fit inside it (that is big) so i think that is the best place for a secret hideout on Pokemon emerald.