So this is one of my favorite spot in Thailand, but it's also the most challenging!
The best view is at sunrise, but this is where it gets difficult: the road is not really a road, more a very narrow path in the mud and rocks, so before you get up to the peak, you have to make a decision of whether to drive up yourself or go up on a rented 4×4.
Personally I drove up myself and it was a bad choice: I had a normal car, and I barely made it to the top, it took me 30 minutes to do 2km at 5AM! And my car was in a bad shape afterwards... Also I had to stop before the end and park in some house with the help of a local and finish by foot.
If you'd like to rent a car, it will cost you 500 THB for 15 minutes (they can take 10 people), but I don't think they will drive you up at 5:30AM. So you'll need to get organized here. Get a hotel nearby (not
many choices), either book the 4x4 in advance, or rent a 4x4 to drive yourself, but be careful on the road.