Reds will be back at the Amex in May after reaching their second successive Parafix Sussex Senior Cup final.
Southern Combination outfit Saltdean United competed well for the first half hour but then two goals in six minutes by skipper Jimmy Smith and Mark Randall put Reds in control.
Smith completed his hat-trick during a 15-minute spell at the start of the second half with substitute Panutche Camara twice on target on what was a comfortable night for Crawley.
Harry Kewell experimented with his formation with no recognised striker in what was a strong line-up. Randall operated as a false No.9. Reds were encouraged to get the ball to their wide men and Smith made runs from deep.
That it took Reds until the 31st minute to break the deadlock was down to Saltdean keeper Rikki Banks, who made solid early saves to deny Smith and Boldewijn and when Moussa Sanoh beat Banks, after he’d been played in by Josh Yorwerth, the ball brushed the far post.
Smith also headed over from a decent cross by Aryan Tajbakhsh while Saltdean’s best moment of the first half came when Kevin O’Toole’s audacious chip from an angle drifted just over the bar.
The deadlock was broken in the 31st minute when Josh Doherty overlapped down the left and picked out Smith with his cross, the skipper burying a low finish past Banks from close in.
Five minutes later another break down the left ended with Sanoh finding Randall whose composed finish gave Banks no chance. Josh Payne also went close with two free-kicks as Crawley ended the first half in control.
Kewell brought on Camara, Jordan Roberts and Dean Cox early in the second half and it was Camara who extended the lead in the 54th minute. Doherty’s long ball sent Sanoh clear and he side-stepped Banks to allow Camara to lash the ball into the roof of the net.
Three minutes later it was 4-0 when Roberts was poleaxed by Matt Fleming inside the box. Referee David Spain pointed to the spot and Smith drilled the penalty into the bottom corner.
Saltdean were starting to tire and Smith completed his hat-trick on the hour with the best goal of the night. Joe McNerney’s pass found him in space and as the defenders backed off Smith curled a left-foot shot past Banks and into the top corner for 5-0.
With half an hour to go Saltdean must have feared the worst but they dug in and Mersin made his first noteworthy save of the night from Kevin O’Toole’s drive.
Saltdean finished with ten men after defender Craig Hall picked up a second yellow card for a foul on Camara, who completed the scoring in stoppage time with a close-range finish from Sanoh's left-wing cross.
Reds: Mersin, Tajbakhsh, McNerney, Yorwerth, Doherty; Bulman, Payne (sub: Camara 45), Randall (Roberts 50); Smith, Boldewijn (Cox 54), Sanoh. Unused subs: Morris, Valentine
Pictured: Jimmy Smith celebrates after scoring the first of his three goals