Placing crown molding at the top of cabinetry is very common in residential design and can be easy to do in Revit. Ideally, I would like to use a sweep with a crown molding profile, but Revit utilizes sweeps only for walls when not in the family editor. The trick to making this an easy process for the user is to create a specialty wall that has the desired sweep profile built into it. This allows you draw the “wall” to follow the front edge of the cabinetry at the desired elevation for the crown molding.
The following image shows the resultant crown molding.