When Retford won Unibond Division One South in 2007/8 but were denied promotion because of their ground, second-placed Cammell Laird went up automatically and the next four competed for the play-offs (won by Nantwich). Presumably, the same logic would apply again if Retford win the league this time and can't go up.
Putting aside how King's Lynn fans must be feeling and the clear financial impact their demise will have on us - just looking at matters on the pitch, if King's Lynn's results are expunged then that's not great news for us. Because they were doing so well, most teams are going to get a game back on us and improved goal difference. For example, Bradford move above us on GD and have two games in hand on us rather than one!