Call the local franchise on the phone. They usually have the local (familiar) captain call you back.
If it is about something right at your location, the trying the radio may be best, but often, they will ask to call or be called on the phone if it is beyond a basic answer.
Wifey B: We always call. We think of the radio more as something we'd use on "official business" such as needing a tow.
Much like lockmasters and bridge tenders and dockmasters and all the others you meet while cruising, you talk to all different kinds but we've found them all friendly.
It's interesting that coming down the west coast from Neah Bay to San Francisco you are able to use the CG stations along the way for bar (the inlet type, not the drinking type) and other information. However, in other places, the go to professionals are the tow captains.
Oh, and coming down the Illinois and the Mississippi, the tow boats as in those pushing the barges were the available knowledge. We contacted a couple for permission to pass and their preference of where and they were helpful and seemed very appreciative that a pleasure boat was giving them respect and consideration. Once years ago when we were with friends on the TN Tom and got stuck at a lock until after dark, heading in an area none of us knew, a tow was incredible help. They took their super spot light and lit all the area ahead of them. Covered at least a quarter mile. Then they told us of the cut off to the marina and how to identify it and even shined their light to assist us there. Wasn't our boat we were on but made me know if I ever got a big boat, I wanted a light like they had.
Everywhere you go there are people glad to help you if you ask and show them respect. Like if it's your first time locking, tell the lockmaster and they'll walk you through and make it as easy on you as they can.
Other boaters will help and answer often as well. Just be careful there. You don't know their experience. We were on the ICW one day and heard a boat in front of us give advice to an approaching boat that was so very wrong. He was telling the boat to keep to the starboard side of the channel and needed to be saying port to the approaching boat. It was starboard side going in our direction not coming from the opposite. We corrected and the guy got angry, then we tried to explain it that his left was the other guy's right and he just wasn't getting it.