I understand that these packages need to be put into the Hull/Vessel from the Laem Chabang Port.
Putting the packages through strand jack/gantry wouldn't be feasible in this case. Whereas, there is an option where we can Roll On the packages to the Vessel through SPMTs which is termed as Roll on/loadout.
The packages hence can be transported from the site (6 km which you specified) and stooled down temporarily at the port. The vessel must be a RO-RO vessel(in which the axles can come and go). The SPMTs along with the package can go inside the vessel, stool down the package on stools and come out and so on for the other packages.
Please check with client, if the scheme is feasible so we can quote for Transport and Roll on of the packages there.