Just unbolt the master cylinder from the booster and pull the master cylinder forward enough that you can either see behind it, or can get a finger behind the master to see if it is wet inside the booster. The only times I have ever had to bleed brakes at the wheels is when there was a part replaced after one of the flex hoses, or there was a complete brake fluid change to get rid of the water laden brake fluid.
Bench bleed the master before changing it, and leave the bleeder lines on (assuming they still supply a bleeder kit with master cylinders these days).
Bleeding at the master after installing it is not done the same as the bleeding at the wheels. To bleed the master after installing it, do not pump the pedal, just loosen the lines, have someone press the brake pedal down and then hold the pedal down as you close off the lines. Once closed, wait 10 seconds and have the helper release the pedal. Wait another 10 seconds, then crack the lines loose about a half turn and have the helper push the pedal down slowly, making sure they don't pump the pedal. Close the lines as the fluid comes out, and have the helper release the pedal after you have tightened the lines. It should only require a couple of bleeds to get a good pedal.