Drawings will use the penset assigned to them.
Layouts will use the 'global' penset assigned to the layouting environment.
Typically a drawing gets it's penset that is saved with the view it is sourced from. If you want to override this, you can select the drawing and edit it's settings. Go to the Properties panel and you will usually see the penset assigned as 'By View: pensetname'. Here yuou can change it to any one of the other available pensets. You can also use Drawing Manager to do this in bulk by selecting more than one drawing at a time. For a more visual approach set up a Drawing List and add the penset to the index fields.
Having said all that though, I wouldn't recommend this as my first choice. I believe it is more logical and more consistent to change the source view's penset, not override the drawing's penset. Then you should have different views for different drawings. This is much easier to manage IME.
As for the layout's penset, there is a global penset for the modeling environment and another for the layouting environment. To change the layouting environment penset, go to any layout and go to Options> Attributes> Pens & Colors. It will have 'Layout Book' next to it in brackets as opposed to when you access the same command from the modeling environment where it will have 'Model Views' next to it in brackets.
Anyway, that's where you change the penset for the layout book. This will affect all elements in the layouts and masters,
except the drawings!
Clear as mud?
Cheers,
Link.