If you can only get 4 shooters, hire someone's kid as a target marker to round out the 5th person. Everyone pitches in $12.50 for the marker, the kid walks away with $50 for the day and you get shooting time.
Max, thanks for the heads up on the campground.
762nato, thanks for the offer. Which direction are you from the range. I usually travel to shoots with 3-4 other guys and my pop-up trailer is 22ft long.