It is risky to put the Aperture library onto a network volume or to acces it by more than one user at the same time. Aperture is not made for Network access or concurrent access by more than one user. The simplest solution for your problem would be to move your Aperture library to a portable, external disk and plug this drive into the mac you are curently working with.
The external drive needs to be formatted MacOS X Extended (Journaled) and the "Ignore ownership on this volume" needs to be set.
The procedure is explained here for an iPhoto Library, but it would be exctly the same for an Aperture library: iPhoto: Sharing libraries among multiple users
As you are using one mac to preview the image from the camera and the other to edit and print it you could set up a fairly simple and automated workflow where the images are taken from the camera into a folder and then into the Aperture library.
You would preview the images in the folder and do the edit and print in Aperture as you normally do. No reason for what you describe for both users to have to access the Aperture library.