Yep, click on the Stage (component window, on left below menu buttons) and there is an option to mass override and CG override the whole rocket. Each component can be individually mass and cg overidden as well, by selecting it from the same window.
Presuming that you want to override the mass of a component (like a nosecone)
Open the window of the component you want to change. Just under the bar where the component's name is, you'll see "Override". Click that.
Click the box "Override mass:", and enter the value you want in the space provided for you (after ensuring that your unit of measurement is the correct one you want), or you could play with the slider bar (if you are trying to achieve some kind of balance point).
Speaking of balance points, you can alter the CG of the component in the same window.
You can export/save the whole thing as a PDF and the simulation results will be included in the PDF. Not the graph but the pertinent stuff such as altitude, velocity, delay times and so. Not 100% sure what all is included. Then just print the PDF. When creating the PDF you can select/deselect options to put into the PDF like centering rings, fins, nose cone profile, etc.
There are also a radio buttons to override the mass/CG of all subcomponents. This is nice when you're weighing/balancing a part (like say a fin can) made up of lots of small pieces. Make sure you have all of the simulated subcomponents in the part when you do that, though!