My ds is 14 and doing GCSE stuff. But we're also doing general knowledge at the same time. We are currently looking at Ireland - history, religion, culture, geography, art, you name it. Also specifically looking at teenage pregnancy, British Government, Trees, Birds and boats.
For an hour and a half in the early morning we do formal GCSE work together, with books/internet and writing.
For another hour at 5.30pm we work together on further formal stuff and I set work for him to complete on his own (usually reading).
During the day time we do a massive range of stuff, anything from a HE event at the uni, to a toddler group (I childmind). This may need 1:1 from me or he may attend something on his own. Sometimes we use tv such as the film, Philomena, which ties in beautifully with our topics of Ireland, teenage pregnancy, religion. Once he's watched it, I discuss it with him or if I'm free I watch it with him and pause it to discuss events.
I occasionally take him to evening events too such as, the theatre or an adult evening workshop which has accepted him.
So whilst we are spending just a few hours a day sat at a table, we are doing a whole load of other stuff together. Everything can be a learning event once you know how to follow it through and it's hard to know when to stop. Generally he's always close by so I can point out how something links to what we've covered, or I can add resources to extend what he's doing or make a note of a discussion topic to be had.