There are tire company tables showing recommended inflation level vs weight carried. Having your rig weighed, each corner, and using the table will give an inflation number (as I understand, round up and use high side number for the axle). Also, there are manufacturer inflation pressure numbers on the door jam.
You asked for max cold inflation pressure - that is the tire sidewall max pressure (80 psi, on mine). That pressure gives the highest load carrying capacity for the tire. Lower inflation will give less load carrying capacity, per the tire company table mentioned above.
2012 Solera "S"
Calif SF Bay Area