Do change that oil before you go Dale. I would also take a hard look at the Serpentine belt. It has ribs (5 or so) on the underneath side that will develop cracks every eighth of an inch or so and if you see this with 3 of those ribs it is time to change it (about $17) and there is a very good chance that you can do this yourself or have a friend do it for free for this 1,000 mile trip.
Are your tires ok? do they have any inside or outside wear front or back?. If they are good n square do they look up to a 1,000 mile trip?
You won't do too bad on fuel. I figure that your make and model will get you 19mpg on the highway or 53gal or $106. If you take a cooler, you can save a bunch on food cost.