Brian,
Transferring the Application Add-Ins is fairly simple. Note to be VERY careful with manually manipulating the registry; there is a lot of potential for causing problems. Just go to HKEY_CURRENT_USER\Software\Bentley\InRoadsGroup\Applications\Version 8.#\[Product.DLL]\AddInApps in the registry. Right click on AddInApps and select Export. Under Export Range on the Export Registry File dialog choose Selected Branch. Export the file and then double click this file on the second machine to add the settings. Note that If these settings already existed on the second machine, they could be overwritten. If you are transferring between different versions of the software, then you will need to edit the registry file with the correct version number before adding any information to the registry.
Transferring the Variable Manager settings is a little more difficult. They are stored under HKEY_CURRENT_USER\Software\Bentley\InRoadsGroup. If you export the selected branch, it will export all of the Keys below it. If you add this information on the second computer, you could overwrite some important information. This may not be desired. If you know how to edit the REG file to only include the variables, then it is much more simple.
I hope this helps.
Thanks,
Jason Smithey