Below are the links to all external (non Steam) mods you will need for the convoy.
Reforma (Mega Resources Included)
Doms Pete 379
BSA Freightliner Classic XL
Mack R series (R700)
7 Zip is needed to extract the .rar files into a folder turning them into .scs files (Required Step)
Note: Having your mods in the correct order prior to the convoy is advised. The proper mod load order can be found in the Official ITC Discord Server.