Other than the elite schools, I suspect you overestimate the standards and requirements.*
If you have a successful white collar career, you are at least a mediocre writer. That may be enough to pass on to your kids and get them into many schools. If you acknowledge your gaps - sounds like you have - even better, now you can fill them with anything from online courses (anywhere from free to expensive), tutoring (expensive), local community college (depends), or even trading favors with other parents with opposite skills gaps (bartering ftw).
* I have a homeschooled kid looking at colleges now and the standards are lower than I expected. He passed the minimum requirements years ago.