Swagman,
Correct me if I'm wrong, but it seems to me like you're not even 'playing' the challenge game; but you just didn't FEEL like driving there to see her. There is nothing wrong with that. Drive to see her because you want to spend time with her, not because you feel obligated or guilty. If she starts complaining again, say something like:
"Listen, you know that I care about you. I try to show you all the time. But there are going to be sometimes when I just want to sit back and relax or when I forget to return a call. It doesn't mean that I'm not remembering you, or that I'm intentionally neglecting you...it's just that I have so much going on right now that sometimes things slip my mind. And when you try to say that I'm being a bad person for not driving to see you it makes me feel like YOU don't care about me. I know you're not a selfish person, but sometimes it seems like you don't even WANT to understand me."
That should seal the deal. Make it sound sincere. Hell, it SHOULD be sincere because from what I've gotten from your post, it's the truth. Don't be agrumentive, just say it like you're confused and you want to believe she's there to support you but it's hard when she's doesn't even try to understand you.
Fvck the challenge game right now. That's a joke. You're way beyond that and her interest is through the roof anyway. Guys on this board think that women left them because they weren't "challenging" enough. Not true at all. Their interest is falling off for 100 other reasons that nobody here will understand, nor accept. But that's for another post.
-Blitz