It's been years since I read that one (even though it was one of my favorites), so I can't remember how far into their reign it was supposed to be. But yeah, that would probably work out just fine.

In fact, if Walden Media was really smart, they'd film PC and DT together (or at least back-to-back) the way the Pirates of the Caribbean sequels did. Simultaneous filming ain't just for hobbits anymore. The only problem I can think of is that it might be too much for Georgie Henley and Skandar Keynes, particularly as they're the youngest of the four.