Do you have a Lug sail of the Sloop? With my Lug sail I just lower the sail, pack it as neatly as I can next to me and row away! My wife or daughter will take the tiller or if I am alone I very loosely lash the tiller, just so it wont fall overboard. It can move freely back and forth allowing the rudder to go with the flow.  

Time worn question, mountains or sea shore?

My take is that, with able-bodied help the changeover ought not take more than 10 minutes with practice, perhaps less depending upon your own experience with sail craft.

Probably best done at first at dockside, then as skills & confidence are gained make an attempt in shallow water, see what changes.

Dan,

     Hope you've just about finished your dory. I've got the lug rig and have the same problem. Family with small kids and some don't want to sail, some love it. I've done the shallow water switch, but found with the kids it's easiest to plan the day from the garage at home, configure accordingly, and then boat the plan. 10 minutes isn't far off, even if the "extra set of hands" is in kindergarten. If you haven't already launched, I bet you'll find that rowing configuration alone gives you way more room in the boat and I've found that if I'm going to row anyway, it's worth leaving all of the sailing components at home. It leaves so much more room so that if anyone feels the need to fight with their sister, they can be sent to another side of the boat without me switching seats with my oars. Best of luck.