Most places in the west. Late March can bring warmer weather, but generally you're ok in most places. It can even be the best time of year - 100% of terrain open, Spring Break wrapping up, a chance for a foot of powder overnight and warm temps during the day.
Having said that, higher elevations tend to fair better. If 'early April' means the second week of April, then I'd strongly urge you to look at higher elevations. It's amazing how quickly conditions can go to sh*t. So, here's my short list of places I'd consider for that sweet spot in the skiing year:
1. Colorado - Copper, A Basin (less family oriented), Breckenridge
2. Utah - Brighton/Solitude/Snowbird (all of which are less family oriented). I'm not as familiar with Park City that time of year.
3. California - Tahoe/Mammoth
4. BC - Whistler
5. Montana - Big Sky/Moonlight
That's a pretty nondescript list.