Here's my concert list of the shows I've seen.
https://www.setlist.fm/concerts/tyketto00Below are the shows Red River Valley Fair has had (or tried to have) from 2000 through 2008.
Red River Valley Fair
June/2000 (West Fargo, ND)
America (rained out)
Kansas (rained out)
Sammy Kershaw
Gary Pucket of The Union Gap
The Grass Roots
CCR
Foreigner
Styx
Red River Valley Fair
June 2001 (West Fargo, ND)
38 Special
Tracy Lawrence
Toby Keith
Beach Boys
Poison "Glam Slam Metal Jam"
Red River Valley Fair
6/15/02 (West Fargo, ND)
Lynard Skynard
Poison "Hollyweird" Tour
(met Bobby & Rikki)
Kenny Chesney
Collin Raye
LA Guns (could have met them on mini bikes)
Firehouse
Ratt
Warrant
Dokken
Heart
Joe Diffe
Tracy Lawrence
Mark Chestnut
Janie Frickie
Juice Newton
Balliey & The Boys
Red River Valley Fair
June 20-28 2003 (Fargo, ND)
Poison "Harder Faster Louder Tour" (met Bret)
Foghat
Joan Jett (rained out)
Def Leppard (talked to Rick Allen)
Cheap Trick
Sawyer Brown
Red River Valley Fair
6/18-6/27 2004 (West Fargo, ND)
LA Guns
Firehouse
Warrant (met the band)
Dokken
Great White
Journey
John Michael Montgomery
Carolyn Dawn Johnson
Loverboy
Eddie Money (met Eddie Money)
Molly Hatchet (met the band)
Red River Valley Fair
6/17-6/25 2005 (Fargo)
ZZ Top
Tesla
38 Special (free show)
Bret Michaels (free show)
(I met Bret Michaels again)
Johnny Holm (free show)
Guess Who (free show)
Montgomery Gentry (didn't go - RTH)
Cheap Trick (didn't go - RTH)
Doobie Brothers (didn't go - RTH)
Red River Valley Fair
6/19-6/24 2006 (Fargo)
Johnny Holm (didn't go)
Jo Dee Messina (didn't go)
Sawyer Brown (didn't go)
Neal Mccoy
Phil Vassar/Trick Pony
Poison and EndEverAfter(got setlist)
Red River Valley Fair
Weird Al 5/22/07
Red River Valley Fair
6/21/2008
Slaughter (met the band, had pic taken),
Dokken
Blue Oyster Cult
As for the best concert at Red River Valley Fair I'd say Poison and Def Leppard (although Def Leppard had to cut their set short due to rain).