The way I see it, since there is no seaport in Harmondale, the party arrived in Steadwick (the nearest port) and tried to get stagecoach passage to Harmondale. Being advised that all the roads in and out of Harmondale were blocked by an invading Goblin army, they hiked overland from Erathia. Noting the presence of the goblins, they took the "shortcut" over the mountain near the small village (something stagecoach could not do) and arrived in Harmondale.

Zedd's Rule: Since all the roads in and out of Harmondale are blocked, there is NO stable service available in Harmondale until ALL of the Goblins in the area including the White Cliff Cave guards AND Grognard's relieving force are eliminated.

I have played three or four games now using this rule and find that I can quite easily defeat ALL the goblins AND Grognard at level 1. (This, of course, yields a nice weapon for a level 1 party)