I'd set of on a 3-day outing from Bangkok intending to rent a motorbike from Nakhon Sawan and drive to a few national parks/sanctuaries. Nakhon Sawan is 100km from the forested areas to the west, but it's the nearest town with advertised motorbike rental. The rental shop pulled out of our arrangement because I was going too far and didn't live in Nakhon Sawan (shame they didn't clarify that before the 4-hour bus to their shop). There is no public transport to HKK, Mae Wong NP, Klong Lan NP, so I was faced with another 4-hour bus and a wasted day. Getting desperate I stumbled on an airbnb ad quite far down the google search results which included free motorbike use. I messaged the guy and asked if it was possible just to rent the motorbike, got a quick reply, a price was agreed and the trip was saved from disaster.
I went to Klong Lan and Mae Wong first. I'll make another post for Mae Wong. Klong Lan is basically just a very tall waterfall and a small nature trail so I won't bother with a separate post for that but worth mentioning the large numbers of snakes... I saw 4 live snakes and 6-8 dead snakes just on the 5km road to the waterfall and back, and around the waterfall.
Onto Huai Kha Kaeng. There is very little signage on the road for such an important wildlife diversity hotspot. A few km before the entrance gate I turned a corner and saw another snake in the road, managed to avoid running it over, looked back and saw it 'stand up' and flare its hood, so a cobra of some sort. When I'd dismounted it had disappeared into the grass. Entrance fee is 200 for foreigners and 20 for thais. 20 for motorbike, 30 for car. I thought that given how easy it is to walk through the jungle here, it wouldn't be difficult for somebody adverse to double-pricing to avoid the fee should they be so inclined (and happy to walk).
Not far onto the main road in the sanctuary and there is a left turning blocked by a gate, but motorbikes can get past. I believe there is a watchtower down here somewhere but it looked more like a ranger station to me, perhaps the tower is further on from that. The next turning off the main road wasn't gated and is passable on a bike, not by car. This trail splits left and right with the left going to a watchtower and right going towards the main HQ area. I stayed at the watchtower for a couple of hours and saw a very large herd of banteng, 2 different boar and a lot of green peafowl. I understand there are only around 550 banteng in Thailand, I counted 25 at one point, so I had roughly 5% of the population in front of me. I thought with all this prey a tiger was bound to burst from the forest and take down a banteng 25 metres in front of me, but it didn't happen.
The watchtower had a large tree in front of it which restricted the view. Somebody had set up a sort of hide in the branches of another nearby tree to get a better vantage point.
Next I walked the Khao Hin Daeng and Home of Tiger nature trails. None of the trails in HKK are marked apart from at their start. The trails are not obvious and it would be easy to get lost so GPS is essential. I didn't see anything of interest on the KHD trail except a few hornbills. I startled a boar on the Tiger trail and also found another watchtower. This watchtower had a small patch of grassland in front of it and I didn't stay long.
Around HQ and on the way out of the park: