My DW formally homeschooled our DD at age 8 through 2nd and 3rd grade in a single year, with a target of passing the state assessment test at the end, and they still spent less than three hours a day doing it. Given that there's no pressure on your situation, as your DD will be ready for K whether you homeschool her or not, you could budget yourself a lot less time than that. Maybe a half hour of reading to her, and another half hour discussing a topic of her choice, per day? Done.
This could be supplemented by age/ability appropriate workbooks, so she can do school work on her own, and your prep work is reduced to, "read the directions, and show DD how to do it." My DD was always delighted when DW brought a new one home. "Mommy, can I work on my math book?" is another one of those phrases you rarely hear outside of households with a little giftie.
Topic-of-the-day stuff in our case got punted to me by DW, and I'd come home from work to a question ambush, so there was no time to prepare. My solution was to sit down with DD in my lap at the computer, pull up some images on the topic from a web search, and describe what we were looking at. That was enough to satisfy her curiosity at that age.
