Mt Climie is located in Upper Hutt, and is easily accessible from Tunnel Gully. It's as easy as going to the very last carpark in Tunnel Gully (There's only two carparks) and then the track itself is right in front of you. It is signposted at the base entrance to the walk, as well as shortly into the climb where there is a fork in the path.
Mt Climie is a 100% uphill track. There was very few periods where the track was semi-flat, otherwise you will be constantly going uphill. However, I found the gradient to be perfect for walking, where it isn't too hard that you can't go on, but not too easy where you can't feel your body working. It was also a gradient where you didn't have to stop for rests all the time, if at all. We also had people running and biking past us, so it is an achievable hike.
The views from the top are absolutely stunning, and make the two hour climb worth it. You have a complete view of Upper Hutt, and Lower Hutt, as well as peeks of Wellington and beyond. There is also a decent view of the Wairarapa on the other side. We went on a cloudless day and the view was breathtaking, photos do not do it justice!