How could I calculate cumulative hours worked on all tasks from project start date to current date (status) to get a comparison between projected hours worked (baseline) and actual hours worked (tracking)?
Update the status date to the appropriate date. Open up the "Work Variance" column. Read the value at whatever level of the schedule you are analyzing.
This assumes you loaded planning values for work and you load actual hours in against each work package.
Assuming you have a baseline: Make sure the Project summary task is displayed, go to the Task Usage view and add the Cumulative Work and Baseline Cumulative Work field to the timescaled portion of the view.