If I am correct, Explorer is the old Dawn Princess - that is a ship I would avoid at all costs - the layout is weird with dead ends in passageways and there was certainly a pervasive sewerage type odour in some areas when we sailed on her as DP. Sun Princess, as one of the three 'sisters' was similar. I could not even contemplate a long cruise on one of the old sisters. From what I have read, the old HAL ships that moved to P&O (Aria and ?) are better.
It is funny to me that many people seem to love the old Dawn, Sea and Sun, but then that is what makes life interesting.