Not sure what will work for this situation; would appreciate any thoughts.
A bunch of us get together two or three times a year to drive the Tail of the Dragon in TN/NC. We usually stay near Tapoco and get on the road at first light to avoid other traffic; getting 3 and sometimes 4 runs in before we see other cars.
We use FRS/GMRS radios for car to car communications for the rest of our daily drives, but on the ToD we lose reception at distances over a mile or two because of terrain.
What kind of radio would I need to call an "all clear" or to sound a warning over the entire course? 5 miles as the crow flies (11ish miles of nice twisty roads); end point altitudes are 900 ft on the TN side and 1500 ft at Deals Gap with a 2100 ft peak just under a mile straight line from Deals Gap.
A bonus would be communication from Tapoco Lodge back the TN gravel lot - 6.3 miles as the crow flies with a separate 2100 ft peak right in between the two.
Most likely, one of us would run from TN side to Deals Gap to make sure there was no traffic, then warn the lead car if necessary; which could be relayed by existing radios to the caravan. Handhelds would be ideal, but if necessary, a couple of us could do external antennas.
BTW - you may see vids of various idiots treating the ToD like a slalom course - we give rookies two runs to keep their car off the double yellow; if they don't get it, they're not invited back. We push the envelope a bit, but we're safe up there.