I have a daughter who will be 5 in February and another who just turned 2 in August, so they're both in forward facing seats. Our oldest can work the chest buckle but she still has problems with the lower buckle, so I just put my knee on the floorboard behind the passenger's seat and I'm able to comfortably reach them both. In some ways it's easier than having a four door vehicle because you don't have to open two different doors to get them situated. On the otherhand you have to leave your wife out in the cold for longer since she can't sit in the front seat until you've finished buckling in the kids.

You gotta have the extensions IMHO.