Drove here on the ring road from Oxford and had no trouble finding the entry and were well directed by workers to the correct carpark area. You pay for your tickets as you drive in, so once out of the car all we had to do was be awed a lot and go "wow" regularly. Entry is via the giftshop, then through to the courtyard where another entry point had our bags being checked by ghurkas! So as I was saying, wow to the palace, wow to the grounds, wow to the facades, statues, front doors, and double wow once you actually enter the building. Enormous, impressive, dazzling.
We did the free upstairs downstairs tour which cleverly took you through several staged rooms with av presentations that outlined the history of the building and its owners. We then did the "other side" of the building where there is something for anyone's preferences - clocks, tapestries, carpets, portraits, china, tea sets, persian pottery, sculptures, cradles, tables, silver, the library, a Winston Churchill display and more!!! Plus the gardens with plenty of spaces to explore - my favourite part was the secret garden, but the formal gardens were impressive too. We even took the 50p train called Winston over to the pleasure gardens but the rain set in quite heavily so we admired the maze but could not finish it. But the model village there was lovely to look at!
One last tip - if you are on the North side of Oxford, it is worth making the run over to Wolvercote Cemetery to see the graves of JRR Tolkien and his wife (see separate review).