The ice is sketchy (not that it’s ever great any winter). Heave right near the north public access. Not sure if anybody plowed or busted drifts on any of the NW or SW flooded roads to get onto the lake that way.
Sinai is like any number of lakes in SD. Clean water and full of structure. Lots of shallow feeding areas you can target eyes after dark.
Personally, I don’t really target the crappies out there in the winter; I don’t like catching small ones and deciding whether to keep them or try to release them when caught in more than 20′ of water hoping they don’t die. That becomes a real problem when the fish are schooled up in the main basin but holding near the bottom.