Do you have a photo of the different screens?
That is so neat!!! Keep us posted on all about it - I'm not smart like you - I'll take all the help I can get :-/
Are you receiving NEMA 183 from the GPS? Would it display from other GPS modules if they give NEMA 183 format sentences? $60 is a bit much for a GPS module for me to spend just yet, but if a cheap module would work... it sounds like it's just reading NEMA 183 sentences?
Looks like I need the WString.h library? Is that the only extra I need to compile your code?
Tell us all about it.
Ken H.