TC is not auto-mounting by default. You can find out which devices have been successfully detected (and a mount point been prepared) by using grep mnt /etc/fstab (to check what devices are already mounted I would use mount | grep mnt). If your device is showing up in '/etc/fstab' it might be just the case of using mount /mnt/sdb1 (or whatever device / mount point you choose) to achieve your goal.
There are conditions where it is necessary to re-run the device recognition (via sudo rebuildfstab). Also bear in mind that when using a USB device for persistence the boot code of 'waitusb=x' (with the value of 'x' being a delay in seconds to ensure the proper recogition, e.g. 5-15 seconds) will be required.
BTW the BusyBox version of 'find' is part of the Core, but to use 'gtkfind' you will have to install the respective extension (which should be 'gtkfind.tcz', IIRC). How either of them would help me in working out the mouning question is a bit a mystery to me, but you might have a cunning plan ...