Out of game:
As stated above - talk with the players, find out what they actually want and determine if the kind of game you are running and/or plan to run is actually right for them. This will also allow you to determine if they are genuinely bored/frustrated or are being jerks and trying to throw you off your game (in all likelihood it's the former, but you never know).
In game:
let them have a fun (relatively) uneventful stroll to the dwarven area where they spend a session or two (or longer) determining that nothing of any real interest to them is going on. If they wish to stay there and explore, well, you can decide if it leads anywhere.
If and/or when they finally make it back to the city. Have some of the plot hooks you dangled earlier come to their logical conclusion:
1) the city is in the grips of an evil politician who is robbing it for all its worth, anyone objecting seems to conveniently disappear;
2) a rampaging orc horde is about to attack and loot the city, for which it is woefully unprepared as the politician is too busy lining his own pockets and about to run for it.
etc.
Showing players that inaction has as much or more consequences as action can be a pretty good motivator.
And if none of that grabs them, maybe your style just doesn’t mesh with theirs – it certainly happens.
As stated above - talk with the players, find out what they actually want and determine if the kind of game you are running and/or plan to run is actually right for them. This will also allow you to determine if they are genuinely bored/frustrated or are being jerks and trying to throw you off your game (in all likelihood it's the former, but you never know).
In game:
let them have a fun (relatively) uneventful stroll to the dwarven area where they spend a session or two (or longer) determining that nothing of any real interest to them is going on. If they wish to stay there and explore, well, you can decide if it leads anywhere.
If and/or when they finally make it back to the city. Have some of the plot hooks you dangled earlier come to their logical conclusion:
1) the city is in the grips of an evil politician who is robbing it for all its worth, anyone objecting seems to conveniently disappear;
2) a rampaging orc horde is about to attack and loot the city, for which it is woefully unprepared as the politician is too busy lining his own pockets and about to run for it.
etc.
Showing players that inaction has as much or more consequences as action can be a pretty good motivator.
And if none of that grabs them, maybe your style just doesn’t mesh with theirs – it certainly happens.