This is changed to a 5-foot wide trailer. As one online comment states, what is the point of building a trailer if you’re not comfortable in it? Go for the extra width.
The sink & stove are placed wider the way you’d expect them to be.
I began to place 1×2, 1×4, & 1×6 boards to see what the framing would look like. But something just doesn’t feel right. It’s 5 feet wide, 8 feet long, and 5 feet tall. Rather boxy. Not a fan.