Quartus WE newbee - old logic designer

That's kind of an ugly one in a schematic(as far as I can tell). The bottom line is VHDL has some nice advantages, but so does schematic. For right now, it's probably worth learning a little VHDL and just dropping that into your schematic. For example, you can create a New VHDL file, go to Edit -> Insert Template -> Vhdl -> Constructs -> Sequential -> Case Statement. Follow the syntax and put into a VHDL architecture(you'll also need an Entity, which is basically a description of the top-level ports). Then modify the case to do your encoding. When you're done, go to File -> Create Symbol for Current File. Then add it into your schematic.

The first pass will be difficult as you'll have some errors, as with any language, but it shouldn't be too bad. There are definitely arguments for going to VHDL, but if you're happy with schematic, stick with it and just have the comfort that you can use an HDL if and when you need to.