Hi, Thanks for your question. Firstly, it depends on the location for gorilla treks. I can only speak of the Virunga Mountains and Volcanoes National Park, in Rwanda. When flying in and driving to the location, I understand that access is certainly easier here than in Uganda. You can fly into Kigali and you are only about 2-3 hours drive away from the National Park. On the day, you arrive at Park HQ very early and it can take a couple of hours before you are allocated a habituated gorilla group. This is where location and altitude can vary. Once you have been allocated the group, you have to drive to the start of the trek. This drive can also be 1-2 hours and you need your own driver to get you there, or drive yourself.Then you start your trek. If you are going to go with an tour organisation, my advice is to research carefully and choose an organisation based in Rwanda. Despite research, we did not make a good decision. We were lucky enough to be allocated the Susa B group which are found on Mount Karisimbi, meaning covered with snow. I guess this says something about the altitude. It can depend very much on where your gorilla family are at the timeout the trek. We climbed a bit over 2,000 metres. However it didn’t seem to take us that long- a couple of hours. The Susa B group was part of the original group which Diane Fossey studied. It grew to become a family of 54,then there was a natural split. Now it has been renamed the Igisha Group. We had the privilege of observing about 15 of the 23 in this group, including the 27 year old silverback, a younger silverback, a two month old and five month old, adult ‘couples’ and some juveniles. I would count it amongst one of the greatest privileges in my life. The trekkers and guides are very patient and ensure the group stays safe and together. You can pay for the services of a local to carry your pack and assist you. This is a great way of giving a little to the local economy. It can also be quite steep in places and as you ascend to higher altitude, you may notice yourself feeling a little breathless. We had a wide age range in our group of seven- from young dedicated selfie takers, a keen American photographer ( who got a permit the day before) and we two Australians who were the seniors of the group. A moderate degree of fitness is advisable. The Susa A and B groups are often the hardest to track and see, as they move around a fair bit and can go much higher up. No matter which Gorilla family you are allocated, it is an experience you will remember for the rest of your life.