A good way to condense the training is to break it into an on-line part and an in-class part. The on-line part can start with a pre-course session that brings all the users up to a level of knowledge of basic terms and ideas that are required to take the in-class part. After the in-class portion, another on-line course can be given to ensure that the learners remember the pertinent points, have more examples available about application of the pertinent points, and have a chance to refresh/gel the concepts covered in the intensive in-class portion. The adage about "tell them what you're going to tell them, then tell them, then tell them what you told them" is very applicable here. In the pre-course, prepare them for the main course. This can include a lot of foundation material. For the employees who already know the material, they can quickly skip over (and they won't feel like you wasted two days of their time with it), while for the employees who aren't yet familiar, they can spend as much time as they need to get up to a basic proficiency level. One of the keys to making on-line training successful is to present each concept 4 or 5 different ways since each learner will benefit differently from the various presentations. Instead of just having PowerPoint slides posted on-line, each page should have content (or links) such as main ideas, case studies, step-by-step procedure, detailed explanation, history of the approach, a quiz (non-graded), a test (graded), a field study, or an exercise. This gives the learners enough opportunities to view the material that they can learn it without having to have an instructor hold their hand through every detail.
As you look over the course outline, it should become apparent what material is the most critical. This material can be presented in the pre- and post-course, but it is essential that it be presented in the face-to-face sessions.