Much more on the east side, you should consider the sun road either going to the west side or to the east, since you want to be on both sides.
If you decide just two days on the east side, visit the scenic Many Glacier area and spend it hiking either the Iceberg Lake or Grinnell Glacier trails, or the valley portion of the Swiftcurrent Pass trail . Or enjoy the boat rides on Swiftcurrent and Josephine Lakes and join the short ranger-led hike to Grinnell Lake. Also spend some time exploring the rustic but magnificent Many Glacier Hotel, known as the “Showplace of the Rockies.”
If you have a third day, hop down to Two Medicine and explore this beautiful area in the southeast region of the park, including several great hiking trails,taking a boat ride or canoeing on Two Medicine Lake, and other activities. Or, as an alternative, take in the sights along Lake McDonald on the park’s western side.