Neutral-Ground bonding with generator (no utility power)
Pull the bond, drive the rods at the panel
You are correct that you need to have the panel unbonded since the generator already provides the bond.  Practically speaking, though, unless you want to leave a bunch of copper laying loose for someone to run off with, you'll be using a #8 Bare Armored Ground (BAG) cable between your panel ground bus and a pair of 8' ground rods 6-8' apart.  Note also that if your panel doesn't come with a ground bus, you'll need to fit one (many main breaker panels simply don't provide them fitted from the factory on the assumption they'll be used as a main panel for a building).