Tuesday?
As to the day of the week.
This can be counter intuitive. Often visiting sites like this on the weekend results in shorter lines in the islands.
Reason - most visitors arrive Friday - Monday and depart on the same. On arrival days they tend to stay close to the hotel or the airport. Therefore, other sites which don't pull resident visitors can be less busy on weekends (this excludes beaches obviously).
Anyway you will have an impressive visit.
Aloha,
Lihue 1k