The roadside inspection blitz is May 14 through 16, so check the brake valves now.
Inspectors will be on the tractor protection valve, the trailer supply valve, and the anti-bleed back valve. They will also look for alcohol and drugs. Those are the things that park a truck.
Do it in your own yard
Hook the trailer and look at the gladhands. Charge the lines. Listen for a leak. If a valve will not hold, fix it this month. May 14 is a bad morning to find out the trailer will not release.
If a driver cannot pass the conversation at the scale because of alcohol or a controlled substance, the load sits. That part is on you before the truck leaves.