Jim Thorpe, the inaugural winner of this event in 2001, Doug Tewell, Bruce Lietzke and Mark McNulty are knotted in second place after opening rounds of 6-under-par 65.
Simpson wasted little time in breaking in red figures with a birdie at the first. He then rattled off five birdies in a row from the fifth to make the turn at 6-under 29.
He started off his back nine well with a birdie at the 11th, but fell back to 6 under par thanks to a bogey at the 12th.
Simpson parred his next four holes, then drained a 9-footer for birdie at the 17th. He had a decent look at birdie on the closing hole, but missed. Simpson will now take the lead after the first round for the third time in 2006.
Simpson is winless on the Champions Tour since joining the circuit toward the end of last season. In 2006, Simpson has two runner-up finishes - at the Turtle Bay Championship and the Puerto Vallarta Golf Classic - but is now ready to break through to the winner's circle.
The four players knotted in second took different paths to their 65s.
Thorpe collected six birdies in a nine-hole stretch around the turn after a birdie at the first and a bogey at the fourth.
Tewell started on the back nine Friday and was 3 under par with three holes to go in his round. He birdied three in a row from the seventh to get within one.
Lietzke was the only player at minus-6 who went through his round bogey-free.
McNulty had sole possession of the lead at 7 under par thanks to three birdies in a row from the fourth. He parred No. 7 then mixed five birdies and one bogey over his next six holes.
McNulty dropped a shot at the 17th and had 12 feet for birdie at the last. He missed the putt to stay in second place.
Loren Roberts, a three-time winner this season, Graham Marsh, Mike McCullough, Gil Morgan, David Edwards and 2002 winner Bob Gilder share sixth place at minus-5.
Defending champion Tom Jenkins, who outlasted 2004 winner D.A. Weibring in a playoff last year, posted a 4-under-par 67 and is part of a group tied for 12th place.