"I'm having trouble finding a map of all stops."
It's not easy to get 5,700 train stops onto a single map.
https://geoviewer.deutschebahn.com/maps/#/context/ISR/275618
It is unclear whether you are actually doing heavy sightseeing in places that WILL require trams/buses/subway ride - like MUNICH and FRANKFURT. Most of your destinations are smaller places that do not require the use of trams, subways, and municipal buses. And if Frankfurt and Munich are just transit points, then the fact that the GRP does not include these things might not bother you that much. Two smaller places you will need buses:
Füssen: buses between Neuschwanstein (which tends to drive tourists to Füssen in the first place) and Füssen
Baden-Baden: buses between station and town
The GRP does in fact allow the use of the S-Bahn system, which might be of some limited use within Munich and Frankfurt.
FRANKFURT S-Bahn: https://de.wikipedia.org/wiki/S-Bahn_Rhein-Main#/media/Datei:Liniennetz_S-Bahn_Rhein-Main.svg
MUNICH S-Bahn: https://upload.wikimedia.org/wikipedia/commons/e/e7/Karte_der_S-Bahn_M%C3%BCnchen.png
NUREMBERG S-Bahn: I used this once to reach the Nazi doc center / rally grounds... The Dutzendteich stop gets you within a few minutes' walk. Otherwise, Nuremberg is a very walkable city.
https://en.wikipedia.org/wiki/Nuremberg_S-Bahn#/media/File:S-Bahnnetz_N%C3%BCrnberg.png
SALZBURG: Both the GRP and the Deutschland-Ticket get you there. Neither the GRP nor the Deutschland-Ticket helps you get around within this city.
COLMAR: Not served by either pass.
If you buy just the DB saver fares for long-distance trips (looks like you'd have at least 4 of those to buy) and use the Deutschland Ticket for the rest of Germany, that will be good coverage and will likely save you some money. But... there are some other considerations:
The Deutschland -Ticket covers a CALENDAR MONTH. If your trip covers days in different months, one D-Ticket won't cover all your days.
The Deutschland-Ticket does not cover any high-speed trains. Should you mistakenly board a high-speed train with only this ticket in hand, you may end up getting a hefty fine for traveling without a ticket - and be required to pay the full fare for that train ride as well. The GRP allows travel on ALL types of train, so it's a type of "insurance plan" for mistakes.
The GRP allows you to take any train at any hour - and you can make choices about which days you travel during the period of your pass. The saver fares OTOH are date/hour-specific and non-refundable. You must travel at the hour you booked weeks or months before your trip, or you lose the ticket and you must then buy a new ticket - there's no changing your plans - no leaving a place earlier or later than scheduled (whether you are sick/injured or just slept in and missed your scheduled train, it doesn't matter.) So again, it's an insurance plan that allows you to be human and make mistakes.