pedal travel help needed

The pushrod is accessible by unbolting the m/c & moving it forward, way from the booster. If you are lucky, there will be enough movement in the attached brake lines so that the lines can be left attached to the m/cl. If this m/c & booster combo worked before, then this is will not be the problem, more likely what I described in #5.
This problem would NOT be caused by omission of the res check valve.