Confusing title, apologies!

Tldr: dad is a Long haul trucker, needs a printer in his truck. Printer seems to require an internet connection to verify itself with HP because Fuck Me, Right? Wifi Direct to the printer Did Not Work, so I set up a router just to see if a wan would work. Now we can see the printer, but it still will not print. I suspect, because HP Fucking Sucks Ass, printer/app require a connection to their shit.

How do I fake this? Truck DOES NOT HAVE THE ABILITY TO HAVE AN ACTUAL INTERNET CONNECTION! Including cell connection, thanks Rural Illinois and Indiana.

Help me, Obi-Wan Kenobi, you’re my only hope!