If you are playing Pokemon Ruby or Sapphire, the battle at Lilycove City was the last rival battle. The same goes for Pokemon Emerald, but you can visit her again in Littleroot Town, where she talks about needing to find a lot more Pokemon for her Pokedex.
you can get a master ball by winning the lottery in lilycove
She goes to lilycove and waits.
North of Lilycove....
after beating the elite 4 go find it
On the lower end of Lilycove City, right next to the Harbor.
Surf right from Lilycove after beating the team Magmas Base
no, you don't need to. You proved yourself master after beating Steven.
After beating the gym leader, head right of fortree city until you reach Lilycove City. You will meet up with May at Lilycove mart. Go back where the Safari zone is and right in front of it, you will see an opening of water. Use surf to get to Mt.Pyre. Explore it. You will receive your next objective from there.
you can get a master ball by winning the lottery in lilycove
You have to cross the water. There are two things to do before that. YOu have to beat your rival at the MegaMart in Lilycove and to beat the Team Aqua from their base at the shore of Lilycove.
IIRC, it's in Lilycove. She's blocking the door to the Lilycove department store.
Typically, Pokemon Liquid Crystal should not freeze after beating the Elite Four. You may need to restart your system before you fight them next time.
No, you should never beat a horse. Beating a horse will cause them to lose trust in you and they may possibly fight back.
No you cannot. Your battle with her in front of the Department Store when you arrive in Lilycove is the last time you formally battle her. Other than that she appears everytime you defeat the Pokemon League.
She goes to lilycove and waits.
in lilycove city
North of Lilycove....