I seem to remember I spread mine over three or four sittings...it's been a while though. I prefer to focus on a small number of things at one time and was doing it lone warrior style like the OP while working full time. I only had weekends free (work ran well into my evenings at the time) and used to go into the office to study....quieter than home. I felt like I never left work for almost a year!
Break it up into manageable chunks if you can. I remember that I just couldn't get to grips with one part of Gen Nav. It was only worth three marks so I elected to ignore it completely and focus on what I was better at. Guessing would likely have given me at least on point!