Such a fun trip here! Three of us went and had a blast! We had a pretty good haul too (see attached image. We broke some on site, but brought home most unbroken to break them cleaner and cut the most promising ones open). Would definitely go again. The vast majority of crystals contained in the geodes are very sparkly, but don't expect large crystals, those are rare. But they still exist, you might end up finding something really special! That's the fun about it, you don't know what you're going to get!
ADVISE:
Make sure you go when it's not blistering hot, it's VERY hot on those rocks, even when the temperature is in the 70's. Bring LOTS of water and food, and anything to help keep you cool if you go between April and October. Strongly recommend bringing something for shade, as well as knee pads or something to kneel/sit on, and gloves, oh and first aid kits for sure. Bring plenty of tools: shovel, trowel, some form of pick (stronger the better), hammer & chisel, bucket to collect geodes, etc. Do research online before you go, and MAKE SURE YOU ALWAYS HAVE A MAP. There are several ways off the Pony Express road to get to the beds, the best is to take the exit where there's a sign for the geode beds.
Look for round rocks, most are light in color on the outside. If you're not sure what to look for, there are thousands of broken ones all over the place, pick some up and study what they look like on the outside. Some really good geodes, broken AND unbroken, can be found just sitting on the top of the ground, so keep your eyes peeled!
For breaking them, I suggest hammer & chisel, start out VERY lightly tapping and work your way up strength-wise if it's not breaking, working around the edge length-wise to ensure the cleanest break and best view of the crystals.