You will probably drop into 3rd on the hills.
Dad has an '01 with a 6spd, 4wd, and Edge-EZ chip with 3.55 gears. With my 7k TH never out of 6th, 20k combined would pull it down and go to 5th on the steep, 28k combined it would flat land 6th just fine but would need to go to 5th earlier.
I don't ever remember needing to go to 4th unless we had to make a turn.
The lack of gears sucks (I've got a 4spd auto in my '05). Wish I had the 6spd but oh well. You will see 3rd on climbs, and 4th everywhere else. I doubt you will have any issues.