Let's say you (or a Young Person of your acquaintance) have finished all the Harry Potter books.
After which you read "Half Magic" and its sequels.
And then you did all five of Lloyd Alexander's "Prydain" books.
And now, though those were very good indeed, you want something aimed at a just slightly older audience, though not necessarily with graphic bloody violence and panting sex scenes.
Well, you've come to the right place -- i have just the thing, my friend. Step right up and cast your eyes on this little beauty.
While somewhat derivative in detail (but what modern fantasy isn't at least a little derivative somewhere?), the elements are stirred nicely into a fairly original story line that avoids the pitfalls of following your examples too closely with nothing new to say that we see all too often in first novels, while still telling a briskly-moving story that the casual reader will have no trouble following but that will not insult the intelligence of a somewhat more analytical reader.
(1) The elite messenger/diplomatic/spy cadre, the King's Riders, who wear distinctively-coloured outfits (green in this case).
(2) The young person of Good Family who has, thru impetuosity and rash disregard of consequence, gotten into some minor scrape that seems to loom huge in her life.
(3)The scheming nobleman with the Pretender to the Throne in hand who plots against the Crown.
(4) The mysterious grey-cloaked figure who appears to aid the Villains, but actually has Plans Of His Own.
And So On.
Subversions of Familiar Elements:
(1) & (2) The young person of Good Family encounters a dying Rider in the wood; he passes on his horse, sword, Rider brooch and his message to her, makes her swear to carry out the mission, then dies, leaving her stuck.
(3) He's not as smart as he thinks.
(4) By some clever footwork early in the story (at least, i *hope* it was intentional) the author diverts attention longer than i might have thought possible.
Oddly enough, while i certainly caught echoes of Lackey's Heralds in the Green Riders, Tolkien's (and most everyone else's) elves in the Eletians and so on, the author i most found myself thinking of a lot of the time was vintage Andre Norton -- the plucky young (wo)man who suddenly finds herself the focus of Great Events, gradually discovering in himself abilities (s)he never knew (s)he posessed, generally involving some innocent seeming but puissant object or device that comes into her posession apparently innocently...
I must say that my favourite part of the book is fairly early on, when Karigan finds herself taken in and succored by the Misses Berry at their family home, Seven Chimneys (which has nine). Misses Bay and Bunch look and sound like slightly dotty old ladies like your favourite old-maid aunt, but i strongly suspect that future volumes (which i hope to see) may well reveal that they're something a bit more.
An excellent light fantasy read; i'd give it about a PG rating -- there are two brief sequences in which rape is obviously intended, but both are short and non-specific; and while violence (including some rather nasty but not too detailed magical violence) is an essential part of such a story, it is handled well and is not lovingly dwelt-upon in detail.
If you like Tolkien, Lackey, Eddings or Dave Duncan (particularly his "Man of His Word" series; though Karigan is nothing like Rap, there is some of the same sense of see-it-through because it's the Right Thing To Do about her adventures), you need to at least give thei ons a look.