The suite the gang stays in is H666.
Charlie is dressed as Gilligan from Gilligan's island in this episode. This is a nod to the shipwreck but also the theory that Gilligan's island is hell (thus the name of the episode) and Gilligan is the devil keeping individuals who represent the seven deadly sins on the island. Dennis repeatedly references the 7 deadly sins wrath(Dee and The Skipper), Lust (Dennis and Ginger), Greed (Frank and Mr Howell), envy (Mac envious of his gay shipmates and Maryanne envious of Ginger), and Charlie represents Gluttony as explicitly stated and sloth(Mrs Howell) in general.
In this episode, Danny DeVito's character Frank jokes he could be Satan. Danny DeVito went on to voice Satan in the adult comedy Little Demon (2022).