Documentation and backup and restore, for sure. If you don't have those you're screwed.
Clear out any ageing hardware, ageing software, or generally cranky old boxes, if possible. Those 20 hours a week keeping "old Betsy" up and running could be more productively spent elsewhere.
A top to bottom review of practices and procedures. If something is being done wrong, "but we've always done it that way" is not good enough.
Keep it in your mind that your objective should be to make things as boring as possible. You want to be able to come to work in the morning and say "oh YAWN, everything's still up and running smoothly". How does each item you're going to change move you closer to this goal?