I knew some people who filled in for Bob Kingsley on American Country Countdown. He did they same thing. He flew people to his studio (first in LA, and later he moved to Texas), and they would work with his team of writers and producers. Recording a 4 hour show would take all day, because they wanted him to read the script the way Bob read it. It was an experience. That obviously changed as various digital technologies made it easier to connect from other places.
It all makes me wonder how they'll do this new Clay & Buck show. When Clay started at Fox Sports, he did their Saturday morning college football show, and he flew to the Fox LA studios every week to do it. He has been doing the daily Fox Sports radio show from home, and did his last one on Friday. So he has three weeks to prepare for the new show.
If you go to RushLimbaugh.com, they have a billboard of Clay & Buck "Inspired By Rush...Starting June 21."