The phrase 'difficult to proceed' is correct and can be used in written English.
It is typically used when someone is trying to do something, but they are having difficulty taking the next step. For example: "The negotiations have been stalled for weeks; it's difficult to proceed without a clear path forward."
It would have been difficult to proceed without Qatar's assent.
But it turned out to be difficult to proceed from there.
"Without consensus, it really is just very difficult to proceed," the official said on condition of anonymity because of the delicacy of the situation.
But, he added, that, "without the state financing to kick-start the process, it would have been much more difficult" to proceed because lenders were reluctant to enter an untested market.
"Very frankly, my view is that with regards to reconciliation," Leon E. Panetta, director of the Central Intelligence Agency, said over the weekend, referring to the Taliban, "unless they're convinced that the United States is going to win and that they're going to be defeated, I think it's very difficult to proceed with a reconciliation that's going to be meaningful".
"We've seen no evidence of that and very frankly, my view is that with regards to reconciliation, unless they're convinced that the United States is going to win and that they're going to be defeated, I think it's very difficult to proceed with a reconciliation that's going to be meaningful," he said.
The goal of the fledgling company is to partner and work in tandem with cities, which may be a difficult way to proceed.
And it would have been much more difficult to move the proceeds of the sale to Shell and ENI into the corporate equivalent of a black hole, seemingly out of the reach even of Nigeria's anti-corruption commission.
This uncertainty makes it difficult for designers to proceed with confidence, particularly when they know that whatever is currently accepted as "best practice" may soon change.
Thus it would be difficult, perhaps impossible, to proceed with plans filed two decades ago for a tall building on the site, and a visit to this little midblock surprise can re-arrange a New Yorker's view of the relationship between street and architecture.
"Clearly, I've explained it is difficult for us to proceed on cases involving vigilantes because I need the best evidence," he says.
