We have one kid at home, a rising tenth grader.
A file called "D's education" on dh's laptop contains her running transcript, detailed plans for next year, and ideas for her last two years of high school. If anything happened to me, dh would outsource dd's classes to the university (Arabic and math, at a minimum) and to online providers. My life insurance would cover the tuition. The document also lists different homeschool-friendly college consultants who could help navigate the college process, since all that info is in my head right now. She could be graduated and start college early, but I think that would be too much to deal with in a loss situation.
If something should happen to both of us, dd would go live with my sister's family across town until she finished high school. Dsis is cool with our homeschooling plans.