CAD Learning curve & rocketry flight plot are about the same! Steep at the beginning, but level off after a while!
It'll be easier than you think. The pulleys are an off the shelf item (at least I assume so), so I wouldn't worry about modelling them. Ensure your pivot point is clear, and use an angle constraint to move the gantry thru it's motion.. Check for collisions!
It's one thing to model the parts & build the assembly. it's another entirely to make detailed drawings!