We took an Uber right until the Pico da Tijuca hike started. The hike has clear direction signs you can't miss, so you don't really need to pay a guide. The views on top are impressive!
We went with uber to alto da boa vista. The Entrance to the part of the tijuca national park is near the safari hostel. From there we went to the visitors' center where you can get some maps of possible hikes. We deceided to do a tour up to tijuca peak (pico do tijuca) and then…
The highest point in Tijuca Forest has the advantage of a car park three quarters of the way up. The sheer scale of Zona Norte and the Baixada Fluminense can be felt from up here and there is a priviledged view of Macarana Stadium.