I'm about to do what you intend, plant a climbing rose by my house where a door, window, and spigot are placed.

Yes, a trellis is needed for most climbing roses unless the rose you pick is like "Blossomtime" which can be grown as a self supporting plant.
I plant my climbing rosebushes c. 2 feet away from a trellis, and leaning a bit towards it.

Be sure and measure and then cut out a piece of the trellis, before you situate it in its place, so that you can easily get to the spigot.

You need a cold tolerant rose, and so I suggest you look at the hortico.com website because they give the zones in which each of their climbing roses can be grown.

Good luck,
Luxrosa