If you like Telly, you should hit Snowmass in CO and Grand Targ and Jackson Hole in WY.
After thinking about it - why not Wolf Creek? Most snow in CO and an easy drive from TX. If you're going to drive to RR for suspect conditions, you might as well drive the extra 3 hours to get to the best conditions in CO. Plus south fork has tons of housing options.
My fav hills in CO are Highlands/Snowmass, WC, Purgatory, Telly, and the Vail BB on a powder day. We typically avoid Eldora, WP, and anything in Grand or Summit County due to the crowds and quality of the skiing.
The problem you're going to run into w Granby Ranch is that snowmaking only covers 65 of the 406 skiable acres. Otherwise for the price, it's probs one of the best beginner hills in the state. It's a great place to learn before moving into the steeper grades.
If you're going late December you really want a solid snowmaking operation or somewhere like WC that gets massive amounts of snow: think Vail Resorts, Alterra, Aspen Ski Co, Telluride, Purgatory or WC.
Just as a reference point, we usually aren't anywhere near full open by Christmas. Sans last year (snowmaggedon), the normal first round of heavy snow rollers hit the week before Christmas and stay through the first week of January. Sometimes we get hit early for Thanksgiving but that snow usually doesn't last. Meaning the snow isn't really starting to take shape until Christmas at the earliest because the Christmas storms are what's used to create the base outside of the early season upload area.
Two years ago at Telly you were still skiing the ribbon of death until the week after Christmas when we got slammed until just after New Years. You really never know but El Niño typically results in about 4-5 inches of greater accumulation that normal or La Niña years. Doesn't mean it'll happen but SW and Central CO usually do better in El Niño than northern CO.
