Hi Boy Scout,
As the other readers have mentioned, they are not trying to scare you off, they are trying to warn you and give you some great advice. I have been told be very careful about travelling the Eyre Highway in the east west direction as the winds are very strong. I am not sure what they are like the time of year you are going, but we did a trip in June last year up through the centre of Australia and the winds going from Port Augusta up to Coober Pedy made it feel like we were peddling the car. We have a powerful Landcruiser and were towing a small van (level to the roofline of the car), and we were flat to the floor getting to a max of 80kms per hour and using double the fuel that we had over the rest of the trip.
Another tip, do you have two tanks. We did and used both with the wind and made it to the servo at Coober Pedy with a dribble to spare. Always carry a spare tank of fuel for the "just in case". Check how far apart the servos are along that stretch. Where we were travelling, there was on average 350kms between each servo, and the prices of the servo in between towns, were about 20c per litre more than in the main town.
Please allow in your planning, to do the slowest possible time, and the highest possible fuel consumtion then if you do that and do better times and fuel consumption, it would be a bonus.
I am not trying to turn you off travelling, as it is a wonderful experience and something everyone should do more of.
Be wise, travel carefully, and most of all be safe and have a great time.
Be happy - take the family camping.