Part, if not most of the problem we encounter when we come face-to-face with the idea of homeschooling through high school is, very simply, FEAR.  Most homeschooling parents I talk with shake in their boots at the very thought. 
   
Others claim to be fairly fearless, but how they act belies them. They may not think it's fear, and on the surface it may not feel like fear, but when they have a hard time making decisions that they think we have no "authority" to make, and when their biggest "concern" is "requirements", I submit to you that they are walking in fear, at least to a certain degree: Fear of college; fear of not measuring up;  fear of gaps (which call "Gapaphobia"); fear of lab science; fear of not fulfilling requirements; fear of "failing" (us or our kids); fear of - you name it, we fear it.  
   
Now some of these "fears" are rooted in valid concerns!  We want the best for our kids, and we want them to make it in the world, college, and whatever the future holds for them.  However, what I see over and over is people who are not only "concerned" about these things, they are bending over backwards to bow down to them, avoid them, prevent them, or whatever. The last thing on their minds is asking God what he might have in Mind for this particular student's "high school experience."  That idea doesn't even dawn on them because their entire focus is centered on satisfying and complying with the system, making sure they do will within it.  I submit to you that when that is the whole goal, there is no room for what God might be wanting to do, other than to maybe see if He says "yay" or "nay" to  a particular curriculum program.
   
It doesn't have to be all one to the exclusion of the other.  But I guarantee that if your Main Concern isn't seeking God first, then "the other" will take over completely.  God knows exactly what your student is going to need past high school!  But if we "seek first the Kingdom of God" -- yes, even for high school -- then "all these [post-graduation] things shall be added unto you."   :-) 
   
"But how?!" you ask? God is totally practical!  It all boils down to our walk with Him.  It's all supposed to be part of our "faith walk" with Him!  We just get to apply faith to a new area of our lives that was possibly "uncharted territory" for God only because we hadn't invited Him in to that territory yet.  (And He doesn't miss a thing!)  So the place to start is this:  Obedience first; questions later. 
   
Isn't this how it works when we first come to Jesus?  We didn't get to say to Him: "Well, I'm considering becoming a Christian, but first I need to know a few things:  Will I be asked to die for my faith?  (If so, I'm outta here.)"  "Will I have to be a missionary? (If so, I'm outta here.)"  "Will I have to be single all my life? (If so, I'm outta here!)"  "Will I have to live by faith?  If so, how will You provide?  (And how much?  And when?  Cold, hard cash preferred.)"  "What if I'm not very good at hearing You at some point along the way?  Will you have a Plan B to bail me out?"...
   
Nope, we just obeyed and then held on for the ride!  Same with high school!  He will lead if we will "be still [and quiet] and know that He is God"! (and let Him actually be God, to us!)  And as far as that last question, what if I can't hear God: If our heart is truly to hear and obey Him, He will speak!!!  One way or another!! ("My sheep know my voice, and follow Me.")
   
Once you have dealt with all these issues, you will then be free to think and see everything from an entirely different perspective. Not that everything will now be rosy and you'll be oozing with confidence (or maybe you will!), but you will be free -- and you will grow in that freedom as you grow closer to God, and will be able (more and more) to hear God's voice speaking to your heart for your child.  And you'll probably even do things somewhat differently, at least in different areas, for each child, because they are unique and have different futures, different works that "God is preparing (non-generically) beforehand that they should walk in them." A unique future warrants a unique education, right?!?  Not sure?  Just take God's word for it -- on faith!

More information at Barb's Website Homeschool Oasis