Water damage and bubbles under the wall

[sevrin]

I’m wondering how to replace the inside wall on my 28’ travel trailer

[BFlinn181]

You'll have to identify how water is getting into the paneling. Check all outside seams and joints. The interior wall is often made together with the interior framing, insulation, and exterior wall. You'll just have to carefully cut through the interior wall and peel and scrape it off as best you can. Watch for wires and don't cut deep enough to weaken the wall structure.