We did the state-funded virtual school last year for my (then) 8th and 3rd graders. It went really well; there is a text-based curriculum that they send you, and you just follow the online guides as lesson plans. My 8th grader was very self-motivated, and I had to spend very little time helping him; he asked questions when he needed to, did his work, studied, took his tests (all online), and did great. My 3rd grader needed more hands-on assistance, but it still only took us a couple of hours to get through the book-work type stuff each day. There were certain things we had to send in to their teachers (writing samples mostly), quarterly benchamrk tests (didn't count - just measured how far they had come), and, of course, the state test at the end of the year, but they took care of setting all of that up; all we had to do was show up to test.
Our state virtual school only went up to 8th grade, so we had to go with an accredited homeschool program this year for our oldest; he's doing wonderfully with them, too. We started middle DS back at virtual school this year, but they're trying to get their funding re-approved or something - it seemed like we were taking some sort of standardized test every other week. We just couldn't handle that any more, so we're traditionally homeschooling him now, too; it gave him a "say" in his curriculum, and he's been doing really well with it, and it has been a much more relaxed type of learning.
I guess that's a reeeeaaaallly long way of saying that we had one great online school year, and one that got so stressful that we left. The time you need to put in as a learning coach will depend on how well your kids do at being self-starters.
All that said, if I couldn't homeschool for some reason, I would vastly prefer returning to virtual school over returning my kids the current environments at our local brick & mortar schools. JMO, of course.
