Trinnie is a resident of Rivet City. She was resident of Little Lamplight in her youth, and has since moved on. She is found mostly in the Muddy Rudder, a bar located within Rivet City. Occasionally she can be heard arguing with Belle Bonny over the amount she drinks.
Trinnie will ask the player for money to buy alcohol. Agreeing to this will result in you handing her 5 caps. Doing this repeatedly will result in her becoming drunk. She will reveal the location of Belle's her stash, under her bed.
The player can view her medical records if you look at Dr. Preston's terminal. It reads:
|Surprisingly healthy, apart from the alcoholism and other chronic dangers of her line of work. Guess they grow them strong in Lamplight.|