Or maybe by "six paths" it simply means the sage of the six senses?
Sage of Six Paths has a Buddhist meaning to it.
Basically, in Buddhism, the belief is that you are trapped in a reincarnation cycle untill you find true enlightment and put aside your desires.
This cycle consists of 6 realms (fun fact; Nagato chose the names of these realms for his Six Peins).
Those realms rank from 1 to 6 from good to bad. Realm 1 (Naraka in Hindu, Jigoku in Japanese) is the worst and realm 6 (Deva in Hindu, Ten in Japanese) is the best. You get reincarnated into one of the realms depending on how good of a person you are.
Once you master true serenity, you are excluded from this cycle.
The name Rikudo Sennin (六道仙人) literally means Sage of Six Paths.
Roku (六) - Six
Do (道) - Way, path, teaching
Sen (仙) - Sage, hermit
Nin (人) - Person
Sennin (仙人) in English, translates to hermit, sage. Hermit or sage means one who has left aside all wordly things, one retired from society for religious reasons or in this manga's case; training.
In Naruto and Jiraiya's case, the title sennin means that they left society in order to undergo training in Mt. Myoboku.