Hi there!
I'm not sure being a teacher has helped me a lot with home ed, actually , but we do broadly follow the national curriculum - in a couple of hours a day for my primary aged daughter.
Firstly, we cut out all the dross. We don't follow NC for PE, Art, Music, PSCHVE (or whatever), ICT, RE etc. That's not because I don't think those things are important. It's because we cover them anyway in our everyday lives (dancing, singing, home ed gym and ice skating groups, going on the computer, drawing).
That leaves, maths, english and science, with maybe the odd bit of history and geography (although, once again, we found ourselves covering a lot of that anyhow).
This is how I do it. I've bought workbooks for the three core subjects and she does a bit each day. We've had Bond No Nonsense Maths and English, CGP books, Galore Park books, WHSmith books and AE tuition books, according to what suited us at the time. She just works through them. Science once a week, with maybe an experiement based round what she is doing. Maths each day. Workbook English 3 times a week and other writing the rest of the time (letters to people, emails, shopping lists, recipes, nything relevant).
To my alarm when we first started HE she covered the maths curriculum for the year in half a term. I panicked, what next? That's why we've got through lots of books. But you honestly do so much, so quickly on a one to one. She came out of Y4 and she couldn't tell the time properly, this week she would be Y6 and we are starting the secondary curriculum, jsut because I have nowhere else to go with her. That's how efficient it is.
Each term we loosely choose a history or geography topic and study that alongside the maths, English and science. Our first one was romans, she loved that and we had lots of trips to places. We did erosion (lots of beach trips), rainforests, victorians, weather and this term we are going to do world war two. These are all national curriculum age 7-11 topics but we haven't been very prescriptive over them, just studied them in a way that interests her and sparks her imagination.
So that's it (I sound much more structured on paper than I feel I really am, lol). NC covered in 2 hours a day.
As to what they do when they've finished, that's up to them. My youngest is always into something terribly interesting, of her own accord. She's been through origami, astronomy, brainteasers, suduko, drawing cartoons, reading, sewing, cooking, you name it. This didn't happen at first, but has been a product of hours with nothing to do! I never hear her say she's bored any more, ever, yet she has more free time than ever before.
My eldest is interested in a games forum and is on there just about all her spare time. It doesn't worry me; her spelling has improved beyond all recognition and she has learnt all kinds of computing skills (she's currently teaching herself to hack into her wii games - though I'm not sure how honorable that is as an LA aprroved activity! )