Sunset Cruise on the River Styx by Mark Nutter

Time traveling Scottish grave robbers, a sad loner who murderously re-enacts the Boston Tea Party, a jealous husband in pursuit of the tree he believes is his wife's lover, and senior citizens who battle extraterrestrials for their favorite booth at the local diner. They have dark, absurd tales to tell. Come meet them on the Sunset Cruise, and bring a coin for the Ferryman. (He works for tips.)