IN my old 97 limited I used to get 27-28 with a best close to 30 coming back to Denver from the western slope.
Headed to kansas to the lake I used to avg 26 on the way and 24 on the way back. It should be noted I rarely speed, usually set cruise on the speed limit and I worked for a lubricants company so I always had new fluids and the top shelf additives too.
I was also super anal about tracking everything and where I filled up. For 227k miles I tracked every tank, brand, octane and I could tell you which stations from here to durango, to grand junction would yield the best MPG. For me conoco would be 3-4 less loaf and jug was average and shell 87 was the best.
With the "new" 01 we just got we will see if I can do this again.