Your range sounds like a great setup.
I go to the same place as Crim. Great facility, even better people.
Short game - My chipping is improved immensely - can't wait for the good weather. My putting technique is much better.
Hitting - 30 yards is great. Pick a spot on the wall to aim around. (think either a horizontal line for up/down/trajectory drills, a vertical line for left right control (face angle and club path type drills), or a spot or circle (break the glass). At an open range, you don't get that....---a distinct target to hit--
I try to hit a nice draw club path while while striking my 'line' about a foot to the right. When I exaggerate my fade and draw swings, I can see curvature (so I know I can do it, though at 30 yards, if I'm curving it enough to 'easily' see it, I know it's too much - but it helps my learning). It's perfect for face angle drills. I also like to work on up and down. A fun drill with a friend is to try to hit the wall within a couple feet of where the other hits it (sometimes using different clubs even). ((key word is 'try', however, it used to be just random 'spraying' now I feel very confident to get close (more like a few feet, not a couple)))
We also have bays with track man if we are really interested in the true details of our swings..
but - Erik nailed it. At the beginning, the big win is being able to work on contact. For me it's usually about 4-5 days a week - even if it's just 15 minutes over lunch. My ability to hit the ball, shape the ball, control the up/down angle, is greatly approved.
One setback - since it's so easy to just go all the time, it takes a bit of constraint to not just go 'hit' all the time. Having a plan of attack and goals and drills can be left behind for just some relaxing time killing (not that it's bad, but it's different than working on improvements).
I also suspect that when I get back outside, I'll likely be hitting a little thick for a bit.