Little River has an interesting cavern,and you can go quite a distance before hitting the no light zone. You will encounter some strong current but this is great practice. Cow springs,if you become a NSS_CDS member, has a great downstream cavern. Madison allows cavern diving,it is pretty good. Where AJ recommended Orange Grove,you will find that it is smaller with less exploration potential,and once it turns to the right you are no longer in the light zone,but would be good to combine with a dive to Peacock 1. Probably one of the biggest and most interesting caverns is Green,which is part of Lafayette Blue,but right now that system has 10-15 ft at best,need to wait for a prolonged dry spell.