One of the cool things about using a PIC is that once the hardware is done, it's easy to change the code. It's faster to download new code rather than breaking out the solder.
For me, creating the initial hardware design is a stumbling block. I can do block setups of what needs to connect to what, but the devil is always in the details. VirtualBreadboard is a way to draw the circut out and test it. It has the ability to read the output from the MPLabs compiler and use it to drive the simulation. You can do either assembler or C.
You might want to take a look at using it as a practice point. A bonus is the examples from the 123 book have been converted, so you can see the code, see the circuit and off you go.
Once you get the hang of it in the Virtual environment, it may be easier to do the programming on the Vex.
http://www.virtualbreadboard.com/