I just got a new to me 2006 Jeep Grand Cherokee with only 51,000 Miles! It has the 4.7L V8 I was going to use 5w30 M1 but wondering what everyone else uses. I only drive aboyt 7-8000 miles a year.
I'd say any name-brand synthetic, change it once a year. A slight nod goes to Mobil 1 Extended Performance since it is targeted at long-drain intervals, but really anything would work well.
Since it looks like you are going to be running a Wix filter you should be good to go with the 1 year oil change like recommended above. Pennzoil Ultra is a great choice if you can find it, i would also recommend Castrol Edge or Pennzoil Platinum to easily handle your once a year change.