The multi-mod install safeguards against the possibility of USB data lost in two ways. First, the script is to be executed and the user is prompted to insert the USB, only after the reformat feature has been completely disabled. So not even a reboot would result in USB data loss. Only after the transfer completes and initializes modules, will the feature become enabled again. Second, the script only supports ExFAT, FAT, FAT16, FAT32 formats. Each of which, the CAP will not reformat on reboot (over 50 reboots tested).
For Local Content, You may try this (I haven’t tried yet, but reported to work): login to admin->hardware. Scroll down to “To modify advanced hardware settings (WiFi, DHCP, Firewall, etc.) please click here”, click on the “Click Here”. Go to “Backup/Upgrade” tab (mid-left). Click “Generate archive” to download a tar archive of the current configuration files. To restore configuration files, you can upload a previously generated backup archive here.
If that doesn’t work for transferring Local Content settings… from one CAP to another, things become a bit more technical. There are four areas to address: 1: en-local_content, 2: /media/preloaded, 3: /medial/uploaded, 4: associated db. I suspect #1 (standard en-local_module) files remain unmodified. As for 2&3, depending upon what content has been customized, you would need to transfer these two directories recursively (perhaps use rsync). #4 you would need to export the customized db and import it to the target cap.