Some journeys can be extremely expensive and/or involve a lot of stopovers, even though the physical distance is quite short. Due to the political situation it is, for example, impossible to travel directly from the United States to Cuba, even though Key West in Florida is only about 170km (100 miles) from Havana, Cuba.
The best thing to do is make a list of all the places you'd like to see. These places can be countries, regions and cities, as well as monuments, festivals, market places, beautiful spots etc. Then divide the list into:
1) places you have to see at any cost
2) places you would really like to see
3) places that would be interesting if they do not cause a major increase in the price of your ticket
With the list your travel consultant can provide you with a tailor-made solution that will serve you and your needs in the best and cheapest way possible. If you would like to know more about the many popular routes and the various pros and cons of the different continents, or if you feel like combining your own route, take a look here for inspiration on backpacker and round the world itineraries.