Went on the "Royal Day Out" package deal. In my opinion, if you're heavily invested in the Royal family stuff, you'll immensely enjoy the full tour. However, if you're like me, don't know too much about the royal family aside from the most famous ones, you can follow my advise. So the package, consists of 3 activities:
1) King's Gallery - Portrait Collection
This was a nice a walk around the gallery to look at photos taken of the royal. However, you can also do it in a ghetto way by going to the gift shop and flipping the souvenir book.
2) Royal Mews
Quite impressive to see the grand carriages but I felt that the added cost to see them wasn't really worth it. On top of that, on the states room tour, you'll see a basic carriage.
3) States Room tour
This is a must do! The rooms are amazing and to think that Princess Diana, Queen Elizabeth, King Charles and all the royals walked on these grounds...
Overall. skip the package and just get the states room tour.