There is a little parking area right by the DLL fence on the public side. You just park right there and then take the little trailhead that pretty much follows the fence line for quite a ways. If you keep hiking down the ridge, you will eventually drop down into Wheatgrass canyon or bear Hollow (both mostly public). From there if you keep going you will end up at the parking are at the inlet to Causey Res.
The general rule with lightning ridge is you need snow. When it snows the bulls on DLL sometimes cross over and move around a bit. Most the guys that hunt that area are just waiting for a bull to step foot over the fence. I have see a few carcasses that were half and half on the boundary line.
IMO it's too much of a risk, and not very productive anyway. I would find another area where you have a large public area to hunt. You don't want to have to deal with the DLL guys if your bull dies on there.
The best time to hunt that area is either early archery before everybody starts stirring around, or late Muzzy elk (with some snow).
Hope this helps.