I've been practicing at an indoor range for the last two or more years. The target carriers go back 50 feet from the firing line. Over time, I've developed a relationship with the owner so I'm now able to work for a couple hours before the range opens. Im able to set up targets down range and practice in front of the line. Prior to that I had to make do with a lane or two. So here's what I do. I had a number of drills, most of which are stright forward.
Bill Drills: 6 shots into an 8" target at 21' hopefully under 2 sec. (really useful for trigger speed).
Mini El Prez: 3 targets on the carrier, 2 shots on each, reload, 2 shots again on each (with or without the turn) (7 sec.).
Drawn taps x2: Draw from the holster, 2 shots, reholster (do this till your sick).
Reload drills: Load as many mags as you have with three rounds each. Draw and fire x2, reload, fire x2, reload, etc., until you've used up the mags.
Look up the IDPA classifier (idpa.com) and scale it down for the range. All the stages use three targets.
To practice poppers I put as many targets on a hanger as I could manage, draw and fire one shot at each at max distance (poppers are rarely close).
These are just some suggestions. Be creative and don't get in a rut. Change things up as much as you can. Work on that relationship with the owner and the workers. I don't know what your range rules are like. I've been to some that don't allow "Rapid Fire." It can be a problem but I've also found that if you don't shoot the place up and appear to know what you're doing, I've never been asked to stop. At some point you'll want to invest in a shot timer but that can be tricky indoors because of the echos and is difficult with more than one other shooter on the range. Also, with all of the drills, mix up the sequence that you shoot the targets in. Don't always go left to right, right to left. Shoot them in different orders as much as possible. Most important, focus on the fundamentals. Your drills are going to be fairly simple so keep your focus on the mechanics of your draws/reloads, getting your eyes ahead of the sights, trigger control, etc.
Have fun, be safe.
Brian