The tenant refuses to sign a lease and is frequently late with the rent. My other tenants arre afraid of her and she refuses to follow any of the rules... ie gate is to remain unlocked between 7am and 5pm. What are my options?

You can give her a written notice that her tenancy is terminated and she must move out within 30 days. If she fails to move out within that time then you can file a lawsuit for eviction.

Yep, just evict her,