Hi Jurek,
Some locations of mammals from Khao Yai a month ago:
Asian Elephant - couple of sightings around the HQ to past the TAT reservoir area. They were also present (as signs) on both waterfall trails to Hiew Sewat Waterfall;
White-handed Gibbon - best views from the Waterfall Trail out the back of the concrete HQ trail;
Northern Pig tailed Macaque - common
Crab-eating Mongoose - Waterfall trail from Pha Kluay Mai (PKM) campsite - by the largest stream crossing;
Common Palm Civet - common eg round PKM campsite;
Small Indian Civet - open grasslands around reservoir area past the HQ;
Sambar and Red Muntjac - tame around campsites and HQ;
Lesser Mouse Deer - first 100m of the waterfall trail from PKM campsite pre-dawn on the trail.
Malayan Porcupine PKM campsite - but not during busy weekend time. Also in open grasslands by reservoir;
and a probable Leopard Cat - road to PKM campsite
At the moment they seem relatively relaxed regarding driving around at night, for the first couple of hours at least, before the barriers go down at the campsites and by the reservoir/staff areas. If you are staying at a campsite during the week the camp restaurant does not open so you have to drive to HQ if you want eat out. I didn't go up the Radar road at night, it sounded awful during the weekend in terms of the amount of traffic spotlighting - I witnessed the exodus from the PKM campsite of pickups with massive spot lights heading that way!
I did park my car outside the PKM campsite barrier for pre-dawn get aways, but this didn't fully work as there are barriers along the road at the other campsite and around the reservoir areas. Still I found you can be at any trail by dawn as they would lift the barrier around 6am or a bit earlier.
The Elephants were great value, always a real pleasure to see wild Elephants (so long as you're not too close
:
[As an edit given the thread posted above this one, the Ele's were viewed at a distance from a motor, be aware and keep away if on foot, don't go stalking them!]