The aim here is to ensure that both companies are able to access the forest resources of each other. The creation of a Two-way Forest Trust would guarantee that as if the Two-way Forest Trust is created between Forest A and Forest B, being the forest resources of the two companies respectively, then all the domains in Forest A will trust every domain in Forest B and vice versa.
By backing up the important information from the laptop computers to OneDrive, if a hard drive failure is to occur, assuming the salespeople have internet, they may access OneDrive and download any and all applicable data, resolving the issue.