When you say he "rolled" a character, do you mean he chose to make a Gnome Druid and rolled up his stats or do you choose race and class randomly?
Also, why is it odd to have a gnome druid? I think it makes perfect sense for the race. I read the Unther entry in the FR campaign book and I see several ideas for a druid in Unther.
He could be trying to restore the Green lands or his ancestors could be from Methwood and he is returning to his homeland.
Remember, druids don't have to be from the woods either. There are desert, mountain and swamp druids too.