Early April is usually great in Colorado. I'm planning a trip there
myself from east coast. I recommend Summit County area. From there,
Breckenridge, Copper, and A-Basin are within 15 mins. Vail is a 45
min drive. Of those, A-Basin (Arapahoe Basin) is known for having the
longest season, but it's not the best for a beginner. All the others
have lots of green trails.

If you don't stay slopeside and rent a car, you can keep the cost
reasonable.

I would definitely try to go early April, as the later the season, the
more risk there is that you will find less desirable conditions. But
it sure as hell beats going to places like Killington, VT. Every
year that place is flooded with folks from England in March. Talked
to a guy last year. He flew from UK to Newark, then from Newark to
Boston, then drove couple hours to Kton. All I could think was
why? You could get on another plane at Newark for Colorado and be
there in 3 1/2 hours. And in Colorado, Mar is the high of the
season, world class resorts, and excellent conditons very likely.
For Kton, it's chancey, and often not very good, especially later in
March.