Here is some info about skiing brighton's side / back country. I'm not one to give away huge details on all of these zones, so you'll have to explore for yourself for the most part. But here's an overview.
REMEMBER YOUR BEACON / SHUV / PROBE any time you leave the area (and know how to use them). Check conditions - download the utah avy app, and if the signs read considerable or above I wouldnt go out without someone that knows the area.
Yes there are gates that are able to be boot packed or traversed and they also ski back to the lifts. The gates off Milly, Great Western, and Crest all provide access to super fun lines - steeps, pillows, trees, cliffs whatever your heart desires.
The Crest gate accesses Pioneer ridge and peak and is a quick, common boot pack. This skis down into "Wrens Hollow" where you are going to want to stay right to avoid skiing into a lake/ having to slog back to btown.
Milly gates are a traverse across the inbounds "milly bowl" which access rock gardens, a large play ground of everything from mini golf to shit your pants. You can also boot back Mount Milly but there's really only one chute that will put you back into brighton without necessary touring equipment.
Great Western is also a traverse through the gates, it accesses hidden canyon, claytons, and a couple chutes. Once again, stay on the traverse in the outrun to avoid a hike.