We don't have a fixed number to quote you here - Rendon call costs run with the same variables as anywhere else in the area: how far the door came off, whether a track needs replacing versus just re-hanging, and whether rollers or brackets are shot along with it. What we can tell you is that a straightforward one-side derail with intact hardware is a much smaller job than a bent track or a door that's come off both sides, which usually means new track sections and possibly new rollers.
We travel from Arlington for every Rendon call, so there's a trip charge baked into the visit the way there would be for any suburb outside the home base. We'll walk you through what we're seeing before doing any work, and if the door's old enough and beat up enough that a repair just delays a replacement, we'll say so rather than patch it and have you calling again in six months.