The grounds have been closed for law enforcement investigations since the Oct. 1 shooting in which a gunman killed 58 people and wounded hundreds of others.
The defendants in the lawsuit include MGM Resorts International, the concert promoter and others.
A judge signed off on agreement in court Monday that will allow attorneys to photograph and diagram the scene Tuesday.
Concert vendors who left things such as food trucks and sound equipment may be able to retrieve those items as soon as Wednesday.
A judge last week ordered the casino-hotel where gunman Stephen Paddock fired on the crowd to preserve surveillance video and other records in the case.