Where are the ground rods needed?
At minimum you need a rod (or more usually 2, more than 8 feet part, since that gets you out of measuring the resistance cheaper than doing the measurement) at the entrance and the same at the mobile home. Given it's not a huge expense, buy 6 and sink a pair at the pedestal as well to be sure. No points off for doing more than the minimum.

I have 5 or 6 and a 100 foot well casing on a single service entrance, personally.