Three day trip with some variety targeting VT? MRV trip with one day each at Lincoln, Ellen, and MRG is a no brainer (so long as everyone skis). Stay at one place instead of driving between resorts, easy. Don't try to jump back and forth between Lincoln and Ellen. Do Slidebrook and back just to do it, but try to spend a full day working over each mountain rather than jumping back and forth. Only caveat would be time of year, MRG is natural snow dependent and could possibly not be fully open earlier in the season (heck, bad weather can shut the place down in January).