1. Hunting antelope is not like hunting deer. They will be out there all day long; they don't hide during the day like deer do. So, no need to be out to the hunting grounds 30 minutes to an hour before legal shooting light. Wake up. Eat a leisurely breakfast. Get out of the truck to begin hunting at 9:30 AM -- this works just as well (maybe better) than getting out a 6:30 AM. If you want to start early, be careful about walking into the antelope and running them off in the dark because you stumble across them when you can't see yet.
2. My guess is that if there are a bunch of snakes around, you will know it and will be on the watch for them. Where I hunted around Gillette, Wyoming, I didn't see any snakes. Doesn't mean they weren't there, they just were not all over the place.
3. Success rates on pronghorn antelope are about 90%. Thus, any skilled hunter who is getting into an area where pronghorn are known to be present is going to take an antelope. Have a plan to handle the meat. From what I've heard and read, it is vital to get the antelope cooled down rapidly. Field dress right after taking your pictures. Then get on with getting the animal cooled off. Some people recommend putting a couple of bags of ice inside the empty body cavity. The antelope smell, so if you are carrying inside an SUV rather than the bed of a pick-up truck you might want to put them on a sheet of plastic tarp so you don't stink up your wife's SUV. If you are going to hang up to cool, get it hung up promptly. You might consider skinning promptly to assist the cooling off process -- that pronghorn hair really does a good job of insulating the animal from heat changes.