Have a look here:http://www.fencecheck.com/content/index ... Nellis_AFB
Spot 10 is worth a visit early morning, you can see what's in from up there. Most stuff at Nellis deploys there to use the ranges, you don't get too many visitors popping in.
To get a feel for what's there, have a look here:http://www.flickr.com/photos/eor1/
You may get a few other clues here:http://www.nellis.af.mil/library/flyingoperations.asp
so there should be a Green Flag on for the next two weeks. However aircraft doing Green Flag usually work from the revetments on the south east corner, and they usually use RW 3R/21L, which is the furthest away one. If you keep an eye on EOR1's Flickr page, you should see what turns up (if anything, they do get cancelled occasionally!)
They sometimes use both runway directions at the same time, so if you're not careful you'll end up swapping ends and missing things - a scanner is a useful tool! The other option is to follow EOR1 (he's in a white pick up, with EOR1 on the plates), he's there most days so knows what's going on!
The light is best late in the day, the rest of the time you're shooting into the sun, but the end of the day light is gorgeous, as long as you've got something to shoot in it!
70-300 should be perfect, provided you're in the right place. The problem is you wont know if you're in the right place until it's too late to move! It's all a bit of a gamble, but then it is Vegas!
PS some recent samples here. Not mine, but I was stood right next to him!viewtopic.php?f=9&t=45581
The departure shots are from Cheyenne, mostly early afternoon, the landing shots are from outside the Speedway later in the afternoon, but from various different spots.
PPS don't forget to have a look at McCarran, it often gets military visitors, especially at weekends.