Mills posted a 68, while Baryla fired a 65. Wood, in one of the latest groups out on Friday, carded a 4-under 67 to join the Canadians at 9-under-par 133.
Keoke Cotner shot a 2-under 69 in round two and is tied for fourth place while Brenden Pappas managed a one-under 71. The pair is knotted at minus-7.
Mills, fifth on the Nationwide Tour money list and all but assured of a PGA TOUR card next year, started poorly on Friday. He missed a 7-foot par save at the first, but made up that stroke with a 5-foot birdie putt at No. 2.
Mills sank a 25-foot birdie putt at the fourth and two-putted for birdie at five to reach eight-under par for the tournament. He then rattled off 10 straight pars, which was fine as the wind picked up at Empire Lakes Golf Course.
At the 381-yard, par-4 16th, Mills hit a 3-iron off the tee. His 60-degree wedge approach stopped 3 feet from the hole and he tapped in for his share of first.
'Trying to finish first on the money list keeps me focused,' said Mills, who won his last start in Boise. 'I'm trying to get as high as I can so I can get more starts next year.'
Baryla had a much more up-and-down round than his fellow countryman. He began on the back nine and rolled in a 15-foot birdie putt at the 11th. Baryla drained another long birdie putt at the 13th, but left a shot in the bunker en route to a bogey at 14.
Baryla closed his first nine birdie-bogey-birdie to make the turn at 2-under 34. He wedged his approach to 10 feet for a birdie at one, but once again made a mistake to stall his momentum. Baryla hit an eight-iron over the green at two and made bogey.
A strong wedge game vaulted Baryla into the lead. At three, his pitching wedge second stopped 3 feet from the stick for an easy birdie, then one hole later, it was a sand-wedge that set up a 6-foot birdie putt. Baryla two- putted for birdie at five and parred out for his piece of the lead.
'I kept it in play most of the day,' said Baryla. 'I live in El Paso so I'm used to the wind. I lived in Canada, so I'm used to the cold. You can't press to try to make too many birdies.'
Wood bogeyed the first, but rebounded with a birdie at two. He added three more birdies on the front nine to get to minus-8 for the championship.
Wood tied for the lead with a birdie at 12, but lost it right away with a bogey at the 13th. He holed a 30-foot birdie putt at the 16th to stay in a share of first place.
Jason Allred (68), Bob Burns (66) and Jeremy Anderson (68) are knotted in sixth place at minus-6.
Overnight leader Chris Anderson struggled to a 2-over 73 on Friday. He is tied for ninth place with Richard Johnson (72) and Camilo Benedetti (66) at 5-under 137.
The 36-hole cut fell at 1-over 143 and tour money leader Roland Thatcher missed the mark by eight shots.