Richard,
As Einstein said, "it's all relative..."
There is no way to predict exactly how long one should expect the job
application, screening, interview, and hiring process to take. It is so
dependant on so many variables, including the nature of the applicant pool,
that you shouldn't be surprised if it takes longer or even shorter than your
expectations.
Inquiring about, "When would the job start?" might be one way of getting a
rough idea of when they would like to fill the position.