Our family is a square nut trying to fit into a round hole! It feels like we are the ONLY Christian home schoolers who know the earth is old. Trying to find a co-op for our high school child, which does NOT use Apologia material is impossible. On a previous visit to the Reasons to Believe web site I found suggested material and on-line courses for high school children. But I can neither find the link nor remember what I read. HELP!Lara, welcome to the club. If only we could find a way to get all of us square pegs in the same room, maybe we'd feel a little less lonely.
I'm not completely sure which curriculum you're referring to, but my hunch is that it's my Good Science, Good Faith course. (If that's not what you're looking for, then let me know more details and I'll take another crack at your question.) Just to be clear, GSGF is not a science course, per se. It is more like a science/Bible integration course. I recommend marking it as a "philosophy of science" elective on the student's transcript.
If you're looking for a solid science course, I recommend using a regular mainstream textbook like Prentice-Hall or Glencoe. If you don't feel confident enough to proctor a high school course on this level, I recommend enrolling your child in a local junior college. (I'd like to also recommend the BYU distance learning program, but I have still to find anyone who has used this service so I can't fully endorse it yet.)