Many times it is good to be able to reserve a tour and travel itinerary ahead of time to be sure that all the arrangements fall into place without any problems. However sometimes it is not always so easy to do this and it can end up taking a lot of time to book your tour. This is especially the case if you are going to be traveling far from home or perhaps to another continent. However there are companies that offer these types of services, but they work more like private tour guides than a tour operator. In this case all you have to do is make sure that you are prepared to pay the tour fees which depending on where you are going can vary quite a bit.
One of the advantages of working with a private tour company is that they will often be able to tailor your tour to meet your specific needs. For example if you are only going to be visiting Paris or maybe Rome you will probably want to focus your tour itinerary on specific attractions and sites. The advantage of this is that you get to see specific needs in other cities while still experiencing the sites and attractions that Paris and Rome are known for.
The other option you have is to hire a travel platform to help you plan your trip. There are many different types of travel platforms out there and they are very easy to use. Just input your information and what you want to do and the site will create an itinerary that is perfect for your specific needs. Some travel platforms also have tour providers that can come along with you or at least help to plan your tour.