Hi Jim,
that sounds good. You can achieve the "auto-chroot" by editing the .profile (vi ~/.profile) file in your home directory of the main root file system. Busybox uses the ash shell and .profile is the auto load file after logging in into the system. Just add these few lines:
mount proc /wheezy/proc -t proc
mount sys /wheezy/sys/ -t sysfs
mount dev /wheezy/dev/ -t devtmpfs
chroot /wheezy /bin/bash
And you automatically change root to the Debian system.