Sort-of off topic, but Brian, if you don't mind me asking, how do you like the XJ in terms of having the kids in it? I only have one, so obviously the car seat fitting in the middle shouldn't be a problem (or is it?), but in terms of overall ingress, egress, livability, etc., how do you like it?
Too, if you fold the rear seat down (no child seat), can you sleep comfortably in the back?
I use the truck every day for only me, and about 3 times a week to pick my kids up and shuttle them home. Works excellent for that. A couple times last year, my wife used the rig, while I troubleshooted her van, and she had absolutely no complaints about drivability/comfort/ergonomics/etc other than the seats kinda being knackered from old age (puttin' replacements in soon)
We've taken a few long trips up to Ventura/santa barbara in it, and while other things detract from the experience like lack of plush suspension and a need for seat replacements, the roominess was never an issue. We always felt like we had enough room with a yakima box on top, and the rear cargo area.
We use two cosco brand (not costco) booster seats for our 6 year old and 4 year old and a forward facing graeco child seat for our 20 month old.
Once the girls are big enough to not be in carseats, we'll have even more room, and I don't expect I'll have an issue until they're in 5th or 6th grade, honestly.
A montero will not fit three carseats across in the middle row, but will fit two in the rear jumpseats and two in the middle row. just fyi. It's kinda cumbersome, because there's no cargo room with the 3rd row up, and no way to get into the rear seats with a carseat in the third row, other than clambering over. (which is fine, I guess, since its fun for a kid..haha) you would absolutely have to have alternate cargo storage like a hitch box or rooftop box.