In 2015 she made history as the 16th woman trainer to take a horse to the Kentucky Derby, where she ran Bolo to a twelfth-place finish.
[13] In 2009, Gaines had the biggest win of her career when Dancing in Silks won the Sentient Jet Breeders' Cup Sprint at Santa Anita Park.
[17][18] In 2010-2011, Gaines campaigned Malibu Pier to multiple stakes wins and a place in the La Brea Handicap.
[19] In 2015, Gaines brought Bolo to the Kentucky Derby, making history as the sixteenth female trainer to campaign a horse in the race.
[25] In 2024, Gaines's trainee Hot Girl Walk won the $100,000 Generous Portion Stakes in Del Mar, California.
In 2013, Gaines was fined $2,500 and suspended for 30 days after two of her horses were found to test positive for testosterone the previous year.
[31] In 2023, Gaines was fined $1,000 and suspended for seven days after horses in her care tested positive for the banned tranquilizer acepromazine.
[33] In 2024, she was fined and received 1.5 Penalty Points for a medication violation which found the presence of Flunixin, a controlled substance in Big Summer after the horse's win in Del Mar.