The Ibrox club lost the Uefa Cup final and their misery was compounded by losing the SPL title to Celtic.
Smith, who has watched his side play nine games since Queens were last in action, is aiming for a Hampden win.
"This gives us the chance to finish on a high note after the disappointment of the past 10 days," he said.
"It's the Scottish Cup final, it's a big game. There'll have to be something left there if we're going to do well in it," said Smith.
Rangers are looking to add the Scottish Cup to the CIS Cup and Smith said he had no regrets about the club challenging for domestic and European silverware.
"If we had said that we were going to be competing in the final day of all the tournaments we play in, you accept that," Smith said.
"That's more than anything we would have expected towards the end of the season."
Smith said Queen of the South manager Gordon Chisholm would believe they could shock Rangers at Hampden.
"They've had no games over almost a month since they finished, so they could have played a few of ours maybe and alleviated a bit of the problem," he said.
"I think Gordon will be sitting there thinking that Rangers have played a lot of matches.
"If you're going to get to a cup final, you couldn't wish for better circumstances, playing a team who played less than 48 hours beforehand."