road map vs guideline

road map and guideline both are nouns.

Word	Noun	Adjective	Verb	Adverb
road map	Yes	No	No	No
guideline	Yes	No	No	No

As nouns, road map and guideline are synonyms defined as:

road map and guideline: a detailed plan or explanation to guide you in setting standards or determining a course of action

road map (noun)	guideline (noun)
a map showing roads (for automobile travel)	a rule or principle that provides guidance to appropriate behavior
a detailed plan or explanation to guide you in setting standards or determining a course of action	a detailed plan or explanation to guide you in setting standards or determining a course of action
	a light line that is used in lettering to help align the letters