Doncaster boosted their chances of a top-four finish as they widened their advantage over Dewsbury Rams in fifth place to six points.
North Wales Crusaders had the better of the early stages, but it was the visitors who opened the scoring when Welham ran onto a short ball to touch down.
Wilkinson then picked up a dropped ball by Christiaan Roets to send Richard Whiting over.
After Sanderson dropped a high kick by Karl Ashall, Greg Wilde picked up to cross in the right corner for Crusaders.
Stuart Reardon then collected Stephen Wild’s pass to dive over next to the posts shortly after.
Crusaders started the second half brightly and Dan Birkett crossed in the left corner.
Scott Spaven forced his way over from acting half for the Dons, before Seb Martins’s try for Crusaders.
After having a couple of repeat sets, Paul Cooke sent Dave Scott over the line on the last tackle. Then, Steve Snitch crossed down the right flank as space – created by the impressive Paul Cooke once again – opened up.