Much as I admire your initiative, Richard, not to mention your thriftyness, your router/planer doesn't really replace a decent stand-alone planer.
In the time it'll take to do the job with a router, a planer would do a stack of planks...both sides. They're basically scaled down production machines.
The other factor is the durability of your bit. It's going to need resharpening long before a planer blade set will. Where your setup will shine is in surfacing glued up panels, which obviously can't be put through a 12" planer.