largest reasonable camera view distance?

What is the largest far clip plane that could be feasable for a game, prior to getting some kinds of bugs with camea view? i.e. a giant spacecraft on long distance terrain, 28 000 view distance is too much?

It depends on what you’re doing exactly, but normally 28K is way too large and can result in zbuffer precision issues. Typically 1-2K is the most you’d want to use. You can use techniques such as more than one camera to deal with long view distances.