Both roadways should have their talkgroups carried on the Bordentown cell. It's unlikely that they would be carried on Hunterdon with any regularity, as both roadways are a bit too far east of the coverage of that cell. I would expect to see Turnpike activity on the Cranbury site, as the site is basically on the side of the roadway.
Someone who monitors those talkgroups could speak better to it. Maybe they haven't moved over from the SmartZone system just yet, so traffic on the NJICS is still somewhat limited?