I-25 N from Albuquerque

No significant grades. There is a grade before Santa Fe (La Bajada hill), another just after Santa Fe (Gloretta Pass) and then Raton Pass on the CO/NM border. None of them are that long nor steep. Raton on the down side is a good down grade with some curves but nothing to worry about. Going north it is a gradual climb.

8 hours depending on your speed and stops. I generally do it in the pick-up in around 5 hrs at 80+. There is a nice rest area just past Trinadad, CO with a good view of the town and hills.

Walsenburg exit 52 has two gas stations and a KFC/Taco Bell that does a good business with vehicles from the 160/I-25 intersection. My 12yr old grand niece's favorite stop on I-25---She likes the Taco Bell

Quite a lot of variation in elevations between ABQ and CoSpgs, but the passes are not a major worry. It isn't really all uphill, though.

ABQ, NM 5300 ft
Santa Fe, NM 7200 ft
Raton, NM 6700 ft
Pueblo, CO 4700 ft
Co Spgs, CO 6100 ft

Been driving that route for decades. Good road easy drive. Only real grade is Raton Pass, and it is really pretty short and wimpy.

Your toughest pass will by Raton at the NM/CO border. It isn't too bad however. You should find this to be an easy leisurely drive. There isn't much but wide open spaces from Las Vegas to Raton, try not to go to sleep. Can't say if there will be an road construction issues or not. There is almost always some construction on I25 around Albuquerque, it is a tradition there. Pueblo CO is where I25 gets kind of crooked and dangerous, just take it at the speed limit and you should do fine. We welcome you to COS, lots to do around here.

Road was clear when we went through the first week in April.

We do Tucson, Albuquerque, Denver every spring to visit relatives in Denver. Stop at Enchanted Trails in Albuquerque since it is a Passport America park. American RV Park on the South side of the highway at the same exit is also nice.

We stop at Trinidad Lakes State Park just into Colorado North of Raton Pass since we already have a Colorado Parks pass on the truck and that gets us into Denver mid-day the next day.

Stay at Cherry Creek in Denver.

Good roads a good half way stop is Russell's Truck & Travel Center
I-25 Exit 419, Springer, NM Easy in easy out good coffee (extremely hot) and some cool cars.