RFP responses are almost never done by one person: big RFP responses never are. Instead, they require inputs from, and the cooperation of, anywhere from 5 to 75 people. Just coordinating that many people is a serious project management challenge in itself.
Success demands that you tailor your processes and tools to the team you have.
Use software that most people have on their computers and know how to use. That pretty much excludes any snappy desktop publishing application, at least until the final presentation pass. And if it means using PowerPoint instead of Visio for your organization charts, so be it.
Allow for time to be lost in communicating — and enforcing! — the target. And the more dispersed you are (by geography, discipline, and temperament), the more time you have to allow.
Think about how to get the best input from everyone, while not getting hopelessly bogged down in pursuit of consensus. Foster conversation, but assign clear responsibilities.