You don't need to lose your social life, you just need to be able to structure your work. I'm currently working on my PPL and i plan on doing Distance learning with Bristol ground school, i've heard many good things about them, and since i work in the business at the moment, i've spoke to quite a few people who have done it distance learning.
Most of the people who i've spoken to have said they did about 6 hours a week, but it's obviously all in relation as to how well you take things in and work...
I've heard very good things about Bristol ground school though.