Harihar fort appears to be rectangular in shape from its base village. It is built on a triangular prism of rock. Though not very tiring, ideal for all. This trek can be tricky in monsoon as steps will be slippery.
The thing which makes this trek much more exciting as well as risky is the last stretch of vertical steps which are almost at a 90 degree angle. The views on top are rewarding and worth for the risk.
The trekkers can cook their own food and stay in an abandoned cave overnight. Trekking in night under full moon will be magical, but risky. However, during monsoon, a day trek is advised. You will not forget in a lifetime the intensity with which the wind slaps your face as you reach the top.
Spend at least 2 days here. While returning, you can have a swim in a lake nearby.