The Dockers came from 41 points down on Saturday night to post a famous 13-point elimination final win - 11.7 (73) to 8.12 (60) - over the Western Bulldogs at Optus Stadium.
The result sets up a blockbuster semi-final with Collingwood at the MCG on Saturday after the Magpies suffered a heartbreaking six-point qualifying final loss to Geelong.
Fremantle are the least experienced finals team remaining in this year's premiership race, and they'll have to win three straight games on the road if they are to claim the flag.
Collingwood will start as favourites in the semi-final given their home ground advantage.
But Longmuir said Fremantle's record on the road this season, which includes seven wins and a draw from 10 games, would give them huge confidence.
Among Fremantle's scalps are Melbourne at the MCG, Geelong at GMHBA Stadium, and the Bulldogs at Marvel Stadium - along with a draw against Richmond.
"We've won seven games and had a draw on the road. We feel like we're a good travelling team," Longmuir said.
"The game against Collingwood is going to be a big challenge and one we're ready for. We won our only game at the MCG this year, so our players should go in with a lot of confidence.
"The Magpie army will be out in full force, and they'll be strongly behind their team. It's another great experience for our players."
The Dockers entered their elimination final against the Bulldogs with only four players who had previous finals experiences.
After the match, Longmuir quipped: "We've got 23 players with finals experience now, so we should be able to handle it."
One player set for a big future is 19-year-old forward Jye Amiss, who booted two goals and took three contested marks against the Bulldogs.
Amiss, who was sidelined for most of the season with a serious kidney injury, missed a set-shot sitter from 15m out in the second term.
But his 25m set shot after the halftime siren and 48m bomb in the last term showed his class and composure.
Fremantle forward Matt Taberner made his return from a calf injury in the WAFL on Sunday, booting 2.2 and taking four marks from 13 disposals in Peel Thunder's 92-point demolition of Swan Districts.
Taberner has been a fixture in Fremantle's line-up when fit in recent years, but it's unlikely he will push Amiss out of the side for the semi-final.
"Jye's performance was great and we probably couldn't have asked for much more out of him," Longmuir said.
"I won't touch on selection now, but Jye played well, so I'm not sure if his spot is up for grabs."
Longmuir said skipper Nat Fyfe wasn't ready to return from his hamstring injury against the Magpies.
FREMANTLE"S 2022 RESULTS ON THE ROAD
Rd 1 - Beat Adelaide by one point at Adelaide Oval
Rd 5 - Beat Essendon by 48 points at Marvel Stadium
Rd 7 - Beat Geelong by three points at GMHBA Stadium
Rd 9 - Lost to Gold Coast by 36 points at Metricon Stadium
Rd 11 - Beat Melbourne by 38 points at MCG
Rd 15 - Lost to Carlton by 31 points at Marvel Stadium
Rd 17 - Beat St Kilda by 41 points at Marvel Stadium
Rd 19 - Drew with Richmond at Marvel Stadium
Rd 21 - Beat Bulldogs by 17 points at Marvel Stadium
Rd 23 - Beat GWS by 20 points at Manuka Oval
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