I love my guest teacher plans and so do my substitutes! I have emergency plans on hand at all times, plus I can easily edit these for the planned days out.
For planned days I do my best to insert the links to presentations/materials and email it to the sub early or post in the Absence system for access.
For emergency days, I have it printed along with printed materials, seating charts, bandaids, pens, office and nurses passes in a binder with the bell schedule, evacuations plans, office numbers and a nearby teacher contact info for help. My emergency plans are simple but enrichment opportunities for students. I will have a class set of current event articles to analyze, Ted Talks, or a student investigation activity ready. I do vary these by subject so that students don't have the same assignment if they have me for multiple courses. I choose to not have our regular lessons as emergency lessons because I would always be updating them. I choose to use these days to benefit the students as much as possible. Sometimes, the sub changes by period and students don't get the same information, if a true lesson was being presented they would fall behind. This also benefits the students who choose to complete the work by adding to their social awareness.