First, eliminate DST completely. The time should reflect the position of the Sun, and forget the complexity and IMHO bizarre self-delusion, a bad habit.
Second, use a time half-way between Mountain and Central Time (i.e., on the half-hour), and create a North American Time. Give the entire US a single time zone. Imagine all the headaches simplified away for coordinating; communicating; scheduling; conceptualizing all time across current time zones, like the duration of your plane flight, etc. etc. -- all that conversion and complexity will vanish. 'I'll call at 4' means something crystal clear; if you're in Denver, 'be at the SF office for the 5pm meeting' is transparently comprehendable - you know how long your day will be, how long you have to get there.
Yes, people in NY will have sunny early mornings - they like to get up early and can enjoy the more city lights. People in LA will have beautiful late sunsets - they can have a late dinner and watch it set even in December. (Yes, I'm snidely dismissing their concerns; I'm having some fun with it.) It's only half an hour worse than prior distortions.
Best if Canada and Mexico will join in - notice I called it North American Time. The line of current the Central-Mountain time zone border goes right through the center of Mexico; it might work very well there (but someone from Mexico will know more). The challenge is outlying lands, such as New Foundland, Alaska, Puerto Rico, and Hawaii. They may prefer special time zones because of the larger distortions. Nothing is perfect.
China, which is very roughly the same distance east-west as the US, has one time zone. Where is it accurate - central China or Beijing? And how has it worked out?
(Or use Mountain or Central Time, if the half-hour will cause too many problems.)