Oh goodness, don't go giving me ideas for a Robinsonade, Virginia! It's one of those tropes that keeps coming back to me (to the point of being an outright fantasy that we ended up getting so close to on my honeymoon.)
I attempted to write one of these once for the Superman Returns universe and never could get it to work right. Getting the logic to make it work was the problem (although the logic worked a little better with the Routh!Superman and Bosworth!Lois than I think I could get it to work with the LnC pair}. I suspect if you went by the Season One Logic of the kryptonite (that it takes time to recover from it) you might be able to get Lois and Clark to stay on the island a little longer.
Incidentally it was THAT episode that got the Robinsonade so completely ingrained in my mind as a ROMANTIC fantasy. I'd watch Swiss Family Robinson (and read the book as I had it at home) many a time growing up but "Ordinary People" made it a romantic option. Too much so. When I was a teen a wrote a romantic fantasy of being stranded on an island with my crush. It didn't go over so well with him when he found out.
CLARK: No. I'm just worried I'm a jinx.
JONATHAN: A jinx?
CLARK: Yeah. Let's face it, ever since she's known me, Lois's been kidnapped, frozen, pushed off buildings, almost stabbed, poisoned, buried alive and who knows what else, and it's all because of me.
-"Contact" (You're not her jinx, you're her blessing.)
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