I think for this case it is just acceptable as is.

If there are multiple writes in this class I'd reintroduce that helper method with LOD-violation again. If `@config.output` is accessed twice I'd add a special proxy method like: `def output; @config.output; end` with private visibility. 

IMHO *must* be fixed if same navigation (sub) path is used more than once. If you only navigate once it depends on badness of more-loc vs LOD-violation.