GAGypsy-
Winnebago provides wiring diagrams, parts list and the like online (link
here). For your coach, you can get to the wiring diagrams via this path:
Wiring Diagrams
For 2002 Journey 34H:
2002 Journey DL/Horizon P34HD Wiring Diagram Book
For 2002 Journey 34G:
2002 Journey DL P36GD Wiring Diagram Book
Taking the path through the 34H, the wiring diagrams that show the radio are:
Dash Radio Installation (sheet 2)
Automotive Wiring Diagram (sheet 5, zone D28)
The "secret decoder ring" for these drawings can be found at this link:
Wiring Identification Guide
If you want plug-and-play, you will need to fabricate a wiring harness to match the Winnebago 12-pin connector shown in the second drawing (zone D28). This is not that difficult to do if you have a pin crimp tool. If you don't, send me a private message with your contact information and I'll walk you through the process. Also, you may be able to re-use the existing connector. I prefer to create a new plug-and-play harness. How it would be wired depends on what replacement radio you select.
The 2002 Journey brochure (link
here), sheet 5 shows what appears to be a 1.5-DIN radio. You should measure the existing radio to confirm. If I were you, I'd use a 1.5-to-1-DIN adapter (link
here or
here) and install a 1-DIN replacement. Removal tools look like
this, but I've also used four small screwdrivers to perform that function when the tool flexed too much. Some folks have used coat hanger wire loops.
Crutchfield is a great source for replacement radios.