It's doable but it totally depends on how you want to split up your time and it usually leaves room for nothing in your normal social life (I dont care though .. loners FTW!

) .. It depends if you want this part time or full time , usually part time would be on fridays/weekends where you have time off anyway, or it could be for all the week and get rest on the weekends ..
For the weeks:
You have 24 hours a day.
School/work etc takes up 8 of those hours at least.
Sleep depends on part time/full time status, 8 hours is good if you can get it, but I can get along with 4 hours a day fine if I need to, just depends on the person, look into polyphasic sleep methods.
So you have around 8-12 hours 'free' per day, lets say you do two-phase sleeping, two hours in the morning and two hours in the evening, so your time would be divided up like this;
6am:sleep 8am:leave for work/school, eating on the way 8:30: get to school/work, change your clothes there to keep time up .. soon after go in to work/classes .. If you need to you can squeeze in half an hour of sleep at lunchtime, but make sure you have enough food. 4pm: get home. sleep for two hours 6pm: have food (lots of it, enough to last you through the night as you usually dont eat much at dinner as you sleep most of the night) , 6pm-6am FREE TIME
Now here's what I'm saying with NO social time, this also depends
hugely upon family/housemates/SO's , if you can get your partner to go along with you then so much the better

Now theres probably not much to do from 6pm to 10pm in terms of people being around outside, so that can be your studying/social time etc etc
Just a few thoughts ..