Hey chuckrans,
That's a cool song, and it's actually more like a riff instead of a strumming pattern. The first thing you'll need to do is tune the guitar a half step down from standard, and then drop the 6th string to a Db/C# note.

Play a D chord, and lift your middle finger from the first string, and put it on the 5th in the 3rd fret while keeping the other fingers in place. next pick up the middle finger, and put your index finger in the 2nd fret. Now play all the strings, and you should hear similarities to what's being played on the song. It's pretty much just moving through these patterns, but the chorus is a little different. The same pattern is being used for the strumming, but it may take some time to get a feel for it. It's two downstrokes, and then up/down up/down. Since you're technically using open tuning you can hit all the strings when you strum.

Dropping the E string is an old outlaw trick used by Waylon, Hank Jr., Montgomery Gentry, and a bunch of others too. They didn't tune a half step low though, but there's alot of that going on these days. Get a listen to Hank Jr. "A Country Boy Can Survive" where the same concept was used but in standard tuning, with the 6th string dropped to D.

Best of luck to you, and I hope this helps some. Let me know if you need anything else, and enjoy the rest of the weekend.