I have traveled extensively having traveled to 81 countries, and some years ago, my nephew asked me to take his mother on a trip. I recommended to her either China or Egypt because of their long histories, and the many interesting sites. She wanted to go to Egypt, so I took her there and to Jordan.
Some years later, I have visited Israel twice. Knowing how religious she is, I think she would have enjoyed Israel more than Egypt or Jordan.
I think for you, Egypt or China would be a very good experience. Do the river cruise - on the Nile or the Yangtze. You get to visit the important cities that are centuries old, and the sites are some of the best in the world. There's a book by Simon Winchester on the Yangtze River. Read it before or take it along if you go to China and the Yangtze.
Beg and borrow to do the trip you want. You'll never regret it.
Also, do some reading before you go. A good Tour Director will always take you to the most important sites and explain the history. Take a note book, and leave the video cam at home. A compact camera is the best.
If you do end up going to Sydney, go to the Shangrila Hotel's blu bar in the early evening and have a cocktail. It's one of Sydney's memorable sites that many visitors miss. Everybody goes to Gastown, and some to Chinatown.
Have a safe and exciting trip, and post a summary of what you saw and experienced upon your return.