Ngong Hills is located approximately 22km from Nairobi, might take you less than an hour to get there if there is no traffic. It is accessible by public means too; number 11 ‘matatu’ from Railways and you could decide to walk up to the starting point or use a ‘bodaboda’ (motorcycle) up.
Requirements
The entrance fee depends on what one is going to do, however general hiking is ksh.232 per adult and ksh.58 per child. You can see all the othe charges on the vlog; https://www.addikahbelinda.com/2021/11/19/all-about-ngong-hills-and-nyama-choma/
All payments are done via Mpesa hence it will be great to arrange that beforehand. Just like Karura forest, plastic bottles are not allowed, only water bottles, helps to avoid littering. Depending on the time of year or even day, you would want to carry a hoodie/sweater with you, it might get chilly.
Generally, one would not need a guide as the path is just straight all the way and it’s up to you to do all the 7 hills or even just one. The first time I did 4 and this time I did 2. It was one of those leisure walks and an excuse to get away from Nairobi. It is a breath of fresh air and another opportunity to enjoy nature with a great view of Nairobi. I also love watching the huge windmills.
Famous windmills at Ngong Hills 
If you can use the time after to take advantage of the great Nyama Choma joints in these areas 🙂 .