Welcome to the club!
I'm about...half-wayish through my first remodel of a small 21' trailer. Like Gary said, "remodel" can mean a lot of things. I've seen people who gut the entire thing and start from the chassis.
I chose a medium-level project so I've demoed the dining area seating, the bunk beds, the vanity in the bathroom, resurfaced the tub, and put in a new floor. But all of my walls, kitchen, cabinetry, plumbing, and lighting is staying in place. Minimal electronics work, mostly carpentry and redecorating.
You need to start out by determining a few things - what in the trailer is damaged and needs replaced, what is good that you want to keep, what you don't want to keep, and what you have the ability to build or put in place. If you don't have the right tools for the job it's going to be difficult to build some pieces.
Good luck!