I've done it, but not like some of the guys with special rigs set up for it.  All you're doing is taking several rods, rigging up a drop shop type set up and putting a minnow on it or I guess crappie jigs if you wanted.  Set them at what depth you're marking fish and use the trolling motor to scoot around slowly.  They'll load the rod when you get one to bite and it's a great way to catch a ton of crappie, but you don't get to feel the "thump", not as fun in my opinion.  I've also only done this in the winter when the crappie bunch up in deeper water and you can mark them.  I don't do it when they're shallow.   I think trolling for them is the same thing as spider rigging, I don't know about trolling any cranks for crappie with any consistant bite, but maybe you can.

As for now, get some waders and get in the water. That's fun.

Cool!  Good info.  I had heard that this was a post-spawn way to fish.  I like that "thump" myself.  Thanks for the comments!  cw