I have some experience with foreign travel. But, I am not an expert. My experience is borne from trial and error. My wife and I first began to travel outside of the United States a few years after we married. We were in our twenties, young and stupid, plus our travel funds were meager. Frequent flyer miles and other discounts were a significant driver of when and where we might vacation.
In time I learned that going on the cheap means that you have an experience that is less than what you might have had. Also, getting in the car of a foreign cab driver and trusting him to take you and your wife to fun or significant foreign locations safely is a gamble that might work well, not so well, or you might never be heard from again.
My wife got hooked on cruise ship vacations to foreign lands. She still prefers to do that. There are some things that I like about that, but I would like it mostly if I was a glutton who wants to stuff all food that he sees into his face for 5 plus meals a day. You cannot escape the crowd on a cruise ship. You had better be a “people person” because you will be a captive of “people people” aboard the ship. What about seeing foreign lands via cruise ship? You will have about 8 hours per foreign land. Actually you will have less because you will obsess about not getting back to your ship before it sails away. The best sit down meals (steak, lobster) will be served on the ship while you are in port, tempting you to not stray far from the ship while it is in a foreign land.
Now that I am older, I think that foreign travel is best done with people you know, be that extended family, friends, or co-workers. It is especially good if at least one of you is familiar with the geography, language, and culture of the land you all will visit. Go with others and you will have greater safety, a bolder itinerary, and I think you will have more fun. If you cannot do that, consider working with a travel agency that has a long, documented, and high customer satisfaction rating for the country that you will go to. Remember, you will only be in that country for a set amount of time. Do you want to spend it stumbling around asking strangers (while speaking English) where you might sight-see, dine, or to ask where is the toilet?