I don't know about all of I-25, but some sections where I have ridden the access road is really nice. It can be a long way from the noise and traffic, even out of sight. There were lots of prong horn antelope to entertain me. Where I was the scenery was good. The Sangre de Christo mountains were to the west and the views were there without the steep climbs. The actual interstate wasn't bad either. The shoulder was fairly clean and the traffic wasn't super heavy. It was conducive to knocking out long mileage. I think the section into Santa Fe was my longest day ever. That was all south of where you would be riding though. That said if you are thinking of the flatter prarie route it is likely similar.