Chain from PLOP to GRUB2 on another disk

[ocgltd]

I'm thinking of using PLOP (one a cd) to boot a USB hard disk with GRUB2 on the MBR.

1. is there something I need to customize on the PLOP CD to do this?  (Can one even customize the CD)
2. If I install PLOP directly onto the MBR of the USB drive, can I then boot GRUB2 on that same drive?  How?  Would I have to install GRUB2 onto a partition /dev/sda1 first?