The election was to replace former Rep. Alan Nunnelee, who died of brain cancer.
She has at least 26 events over the next month, according to a report.
The legislature failed to pass a bill changing from caucuses to a primary election.
The Republican National Committee is accusing Hillary Clinton of keeping questionable allies.
Sanders suggested the USA Freedom Act doesn't go far enough.
He wants new policies to "prohibit nothing" and "disclose everything."
She reportedly raised about $3 million during an earlier trip.
The senator holds a 1-percentage-point lead over Jeb Bush in new CNN/ORC poll.
It's the first time her favorability rating has been underwater since 2001.
The group will deliver a petition with 365,000 signatures asking her to run in 2016.