The heroes are coming. We’re used to this fact. The whole point of our existence is to get the heroes to come. Acceptance is easy. The issue for us is just making sure that the heroes coming takes as long as possible: you think heroes left to their own devices will manage to arrive at the moment of greatest drama on their own? I’ve talked about dealing with them by distracting them, but there’s also the simple matter of sticking obstacles in their path to slow them down.
The easy way to roadblock the heroes is with, well, a standard roadblock. Man-made structures, rockslides in the sole easily usable pass, fallen trees—heck, in some places you just have to get a bunch of random creatures to sit in an unbroken line across the road. The whole point is to give them something they just can’t get instantly fixed; they’ll have to hunt up a new power, or go Do Something Else While It Gets Resolved, or something. Buys you some time, at least.
What about throwing a natural (all right, usually natural) disaster into their path? The main benefit of natural disasters is that they have one of two effects: either they keep the heroes indoors like sensible people, taking shelter from the blast or the shakes or what have you, or they have them running around rescuing civilians who couldn’t quite make it back in—and often you get an equivalent of both, as they take shelter and then spend a little while helping the locals with the aftermath. Not only that, but a natural disaster can easily create, or in some cases be, a standard roadblock; they’re all known for their collateral damage.
Then there’s just making sure that everywhere they go, something is trying to get between them and their goal: for instance, channeling them through areas with loads and loads of random wild creatures. Some people favor making sure the critters are tough enough that logic would suggest they’d be at the very least a fair fight for the heroes, but that’s not always reliable; others suggest small things the prots could mow through, but that pop up frequently enough to be a tedious nuisance. Adventuring isn’t near as glamorous when you’re being constantly mobbed by small obnoxious things.
See if you can get the locals to interfere. We’ve noticed that “You shall not pass!”, when directed at the heroes, seems to work better when delivered by some random commoner or guard, even one they could probably kill with a backhand, then by a member of our forces. I expect this to be a combination of the Laws of Dramatics and standard heroic squeamishness, but hey, if it works it works. So if you know what the heroes look like, get someone to get the townsfolk to delay them, or just strongly suggest to the townsfolk that it would be in their interest to insist these highly capable take care of the Go Here and Do This that they’ve been waiting for someone to accomplish for ages. (Yes, even if it’s against something in your holdings. Your minions will be warned, and you can reinforce them. Three cheers for traps!)
The big thing to remember when coming up with roadblocks is that it’s pretty likely the heroes will get to you eventually anyway; focus instead on making sure they take as long as possible to get around, and at least you know you’re buying some time.