Okay, I went through the code below again and realized that there's exactly one place (the `this.restoreSandboxes` call in `SandboxManagerFilter.Run()` where you don't have access to a pipeline pack from which to get the config object. I can see two choices:
* Cheat and use a type assertion at that point (i.e. `pConfig := h.(*PipelineConfig)`).
* Add a `PipelineConfig()` method to the PluginHelper API so you can just get at it more easily. If we do this, we might even just remove the `Config` attribute from the `PipelinePack` struct. It doesn't really belong there anyway.

I'm leaning towards option 2.