IMC, the party is just heading off into a realm that was once an great dwarven empire.
Now days, in the vast realms beyond the immediate vicinity of the cities, the land is true, wild frontier. All manner of beasties - lots of giants, trolls and gnolls, as well as plenty of other stuff. Even the odd wandering demon pack.
Sometimes, people who wish to forge a new life for themselves, away from lords and taxes and all the rest, choose to head into this land - to farm, or mine or whatever.
Some of these guys will be warriors.
A lot will be commoners who have learnt to look after themselves. Cause a village of 1st and 2nd level miner's won't last long when a couple of trolls wander into their settlement.
Many will die. Those that survive the harsh environement will have learnt how to look after themselves. To fight. But, essentially, most of them are still just farmers and miners. High levels in commoner, expert et al can be used very well to simulate this kind of character.