With Robin McBryde in charge, Wales face Tonga in Auckland on 16 June and Samoa in Apia a week later.
Wales will be missing a host of leading players with 13 uncapped players named.
"If we pull these two victories off, with our top internationals missing, it will be as good an achievement as I've had with Wales," said Edwards.
McBryde cited previous encounters with the Samoans in as a measure of how big a challenge Wales face.
Wales battled to a hard-earned 17-10 win over Samoa in a group game in the 2011 World Cup in New Zealand, while the last time the two teams met was when the Samoans beat Wales 26-19 at Principality Stadium in 2012.
"Probably one of the toughest games I've ever been involved with coaching was the 2011 game in the World Cup against Samoa," said Edwards.
"It was absolutely tough, a really, really tough game and we were lucky in a way to come away as victors. The game could have gone either way.
"The next time we played them they beat us with a full team out. So if we go over there, on their own ground, and manage to pull it off, it will be as big an achievement as I've had in coaching."
Amongst those missing the trip will be captain Alun Wyn Jones who, along with a clutch of Wales big names, will be on tour with the British and Irish Lions in New Zealand.
Instead Harlequins centre Jamie Roberts will lead Wales 32-man squad for the two tests.
Renowned for the physicality of their game, the Samoans are set to push Wales all the way, particularly on their home turf.
Edwards said Wales must not fall into the trap of trying to match their hosts when it comes to the physical side of the game, but instead focus on their own strengths.
"They've got skills all over the place, great footwork and they've got that power and size as well," Edwards added.
"It's important we don't try to take them on at their own game. There's certain aspects of the game we excel at as well, so we need to put our game on them."
Wales defence coach Shaun Edwards says two victories in their summer tour would match his greatest achievements with the national side.