I've completed the hardware and software updates for the 16-bit register address bus.  I now have the monitor program running (not really a bootloader which I've been calling it).  I have also updated my PUSH/POP commands along with my CALL and RETURN commands.  So my stack is working correctly again.  I also implemented putting variables onto the stack and using them in functions.  The first function I put into the ROM is the BinaryToASCII function.  I push a byte onto the stack, and then call it.  It converts the byte into two ASCII bytes which it then sends over the UART.  I made this function so I can use it in my monitor program to read memory locations and display them.  

I've found coding goes much faster now with the new architecture.  There's a lot less mental gymnastics.  This makes it a lot more fun to code for it as well.