You'll never have a enough time to ride everything at Jackson and that mountain has the biz.
In fact, did you ride everything at Vail or even small little Beaver Creek? People spend their entire seasons at resorts smaller than Beaver Creek and have a great time.
New Mexico has Taos and that's about it. Though Wolf Creek is not an unreasonable drive from there. You will want to change accommodations though. Wolf Creek also gets hammered with snow.
Snobasin and Powder Mountain in Northern Utah would be another good spot to hit. Both are great resorts and have different flavors.
Canada has a few other resorts besides Whistler btw. Kicking Horse, Revelstoke, Red Mountain, Fernie, and many others in interior BC look absolutely sick. Most of those resorts are fairly large by US standards and uncrowded huge terrain. In fact those resorts and surrounding backcountry are higher on my list to hit than the shit show that is Whistler.