There aren't many waters between the Mississippi in downtown west to Waconia that don't have crappies that are caught regularly. Richfield does not allow boats on the waters inside their city limits, but there are a whole lot of other "carry on" waters for a belly boat besides the real well-known bigger crappie waters like Waconia, Minnetonka and Medicine. You probably don't want to try the belly boat in the Mississippi or the mouths of some of the streams that run into it like Minnehaha below the Falls, but there are good crappies all along the river as well as the uncountable Metro lakes and ponds.
For a belly boat check out the smaller city park lakes and ponds. Many of them are sleepers and can be real jewels. My best advice is to pick one that is convenient for you and that looks like it might be suitable for your belly boat and then look it up on the MN DNR Lakefinder website both for lake maps and fish surveys.
There really are very few west Metro waters that do not winterkill that do not have crappies to catch. I assume the same is probably true on the St Paul side, too.