I don't think there are any yet
There is a third party supplement on The High Moor offered on DM's Guild, but even that does not appear to have any detail maps of either city, the Path of Light, or the High Moor. It does suggest locations for various sites in the moor, though, inlcuding Rhymanthiin.
There is this homebrew map, but it does not have a lot more detail on the moor, and none on the city or path. There is this post on the trade way from the Alexandrian, which covers a wide variety of historical maps over the ages that touch the high moor, but none detailed.
Neither does the Forgottem Realms wiki, which is normally pretty good a resource in documenting and referencing sources point to any, Ghosts of Dragonspear Castle, an introductory D&D Next adventure set in the adjacent, eponymous castle also does not have a map for the moor.
A search through old dungeon magazines (which sometimes contain adventures with more detailed maps) also did not yield anything.
So, what to do? Unless another poster here can dig up some help, you essentially have full liberty to define that as you like for your campaign, with no canon material getting in the way. Any of the many freely available town maps could be a starting point. You can find great, free maps at Dyson Logos' blog.
Addendum: @christoper-allan-welsh contacted Stephen Schend, the author of the offical "Blackstaff" novel from which much of the available information originates. Stephen replied:
Afraid I still have not gotten around to mapping out the city or done more beyond rough notes that would only make sense to me or someone who’s worked with me for decades. I’m planning to do bits and pieces on my site this year and hopefully compile something for DM Guild this year as well.//In short all the info that’s out there on Rhymanthiin is what’s known; the closest there is to a map or guide to the city is the last chapter of Blackstaff and perhaps some posts of mine on Candlekeep.com.
That is as close as you can get on there being no official material on the subject.