Cortez,CO to interstate 25

Sounds like 160 to the interstate, thanks for the input,Dave

If you're heading north, you can always head west on US 160 to US 285. From there, head north to US 50 if you're heading to Pueblo or continue on US 285 all the way to C-470 around Denver.

Good advice from dadio24. Makes a lot of difference on where you are going.
US 160 is a very good road across southern Colorado and lots and lots of RV travel it. Wolf Creek Pass going east is a pretty steep climb, but two lanes going up all the way to the top so you can stay in the right lane and take your time. La Veta Pass not nearly as steep or long.
You could also go US 160 over to Pagosa Springs and then south to Santa Fe. No passes that way and a pretty drive most of the way.

It depends on which way you need to go once you reach 25, North or South. Going East on 160 is over Wolf Creek Pass & La Veta Pass, but a scenic route for 270 miles, but can be tough towing sometimes. Or you can go South to Shiprock then to Farmington and South on 550 to Bernalillo for 235 miles. No passes and not a very pretty drive. Big bump on 550 near Dulce, near the Apache Nugget Casino, so slow down for a mile either side.