Started reading Pamela Dean's The Secret Country last night on the way to sleep. My comment so far: Having five children in a portal fantasy, instead of four, is Just Wrong. Four is obviously the Correct Number.
(I'm mostly joking, but there is some small part of me that keeps trying to get the count of kids to come out to four.)
Still, I like it so far, and it is (as Mary Anne suggested when she mentioned the book) giving me useful ideas and tools for my own portal fantasy, which some day I may even continue writing.
One other thought: in John M. Ford's Growing Up Weightless (about which I hope some day to write more), I saw the kids as clearly playing a roleplaying game. Whereas even though the prologue of Secret Country reminded me of bits of Weightless, here it feels to me (so far, and at a gut level rather than an analytical level) more like "playing make-believe" than like an RPG per se. I wonder whether that's a distinction without a difference, whether it has anything to do with my initial misperception of the kids' ages in this book, and whether it has to do with the trappings they use (computer-aided vs pure imagination). And I'm only a few pages into Secret Country, so my perception may change.