I've never been a company man but was always willing to stay and do what it takes to get the job done. That meant staying late, working the odd weekend and checking email all the time. It also meant showing up late to events, missing time with friends and family and putting off vacations and weekend trips.
One day I was 15 minutes late picking up my mother for a doctors appointment. I had stayed late to fix a problem I knew could have waited until the next morning but it "had to be done" before I left. She was upset and crying when I arrived (she was nervous about the appointment) and I felt awful. She died a few months later.
That was three years ago and I still feel awful.
I don't work late (as often), I don't work weekends and I don't even think about work after I leave. When my father needs me, I drop what I am doing and go. I show up on time no matter the situation at work. And I take my vacations - all of it. No email, no cell phone, no contact with work. If there is a problem at work that only I can solve, then there are bigger problems at work than me being unavailable.
We all like to believe we are needed and appreciated at work but the truth is most companies will let you go in a heartbeat.
If you want to "prep" for a vacation, do it for you and an no one else. Your friends and family will always be there, you should be there for them too. You've earned your vacation, take it. Stress free and guilt free.