There is enough at Solitude for you and your daughters to enjoy four days, though as mentioned Brighton is fantastic and right there. The others who have replied, I think, were thinking mostly from the perspective of advanced skiers... and from that perspective, I agree with all their comments.
There is far less terrain quantity and variety marked green circle at Solitude, when compared to Telluride, Steamboat, Whitefish, or Big Sky. There's a bunny hill that doubles as the route between the village and the main base, with a double and surface lift. And the Moonbeam Express which is a Minnesota-size lift in the heart of the ski area, with green and blue runs, and access to more of the mountain--so it can be pretty congested.
I'd say it depends a lot on your wife's situation and personality whether it's enough for her. The other mountains you mention have long smooth green cruisers through large sections of the mountain, allowing exploration and long gentle runs without re-boarding the lift... the only somewhat comparable experiences in Utah would be Deer Valley or Powder Mountain. Brighton offers more green-marked variety, but still not a ton.
