Does the fleeing of the earth and heaven in Revelation 20 match Peter's description of everything melting with fervent heat?
Yes. In Revelation 20, the earth and heaven flee away, and no place is found for them. This matches Peter's epistle, where he speaks of everything melting with fervent heat. Revelation 21 then presents a new heaven and a new earth, explaining why the old disappears.
Les explains that the great white throne is strictly for unbelievers, and when Revelation 20:11 says the earth and heaven had fled away with no place found for them, he thinks that is what Peter is talking about in his epistle—everything melting with fervent heat. Les then points to Revelation 21:1, where a new heaven and a new earth appear, which is why this earth will disappear from view. He also notes the lost will be resurrected out of hell and stand before God in resurrected bodies fit for the lake of fire, not glorious bodies like believers receive.