White Box Middle Earth

What to do about Tolkien?
The White Box can handle a lot of campaign settings right out of the box, but the real joy for a referee is creating one's own world and seeing it come to life through play. White Box has been described as a creative re-imagining of the literary sources that inspired it, including among others the work of J.R.R. Tolkien. Early printings of White Box list hobbits as a playable race and ents and balrogs as monsters. At least one illustration is labeled as a nazgul. Anyone who has read Lord of the Rings (LotR) or seen the Peter Jackson movies will recognize a dungeon full of orcs and the wilderness adventure where a party of mixed characters travels cross country, having many encounters along the way.
Middle Earth is incredibly well documented in the many published works, including some licensed game materials which have appeared from one publisher or another over the years. The interested referee might draw on one of these sources for a campaign idea or can, as I prefer, develop a campaign around a map area and a single line of text (or no text) from one of the sources. It is not necessary to involve well known personalities in the campaign and in fact I rather prefer to not do so and let the PCs be the main actors. Not every adventure need result in the destruction of Sauron. Many adventures can be to thwart lessor minions or achieve personal goals important only to the PCs.
White Box is written to encompass an eclectic style of play that blends elements seen in many different fantasy sources and therefore includes things which may seem out-of-place in Middle Earth. The Third Age is one of declining magic and departing elves. It can be described as a low-magic setting, whereas the default for White Box is high magic with crackling lightning bolts and exploding fireballs. This disparity can of course be addressed in one of two ways, tone down magic in the rules or bring the setting into line with the default rules for magic. I personally prefer the former.
Balance between character classes in White Box is a matter of some complexity (if it exists at all). Any tinkering with the classes and their abilities may "unbalance" things. Having said that, I don't worry a lot about it. It is easy enough to remove certain magic heavy classes such as the magic user and cleric or modify them. Spell lists can be trimmed or re-written to include a more Middle Earth themed magic than the default "Vancian" system, which is the approach I favor. Elven magic seems more music/song based while dwarven magic may involve tracing runes and muttering secret incantations. Herbal lore can replace magic in many ways, especially healing and other clerical spell effects and seems more in keeping to the spirit of Middle Earth than deity worshiping clerics wielding divine magic outright. More traditional White Box Magic Users would be rare and could be limited to the Istari, certain "older" elves and followers of the Shadow. White Box is a system of relatively few character classes and in order to both provide players options and keep close to the sources, adding a couple character classes such as herbalist and ranger makes sense.
The bestiary is another setting specific element of the game that can greatly define the play milieu. Again White Box includes many elements that are consistent with Middle Earth and many that are not. Removal of those monsters that seem inconsistent and adding to the list additional monsters found in the Tolkien sources seems the obvious solution. Orcs/goblins come in many forms in Middle Earth and the basic White Box goblin and orc will not do them justice without modification. Scaling seems a good option, making orcs available from 1 hit die or less on up to 8 or 10 hit die depending on the "power" of the orc. Giving undead special powers that more closely reflect their role in the source books is another way to both add consistency to the milieu and increase the horror element of the game. My reading of LotR suggests the Shadow forces were much more creepy and scary than come across in any of the movie versions and I like to run my version of Middle Earth this way. Therefore some mechanic for corruption needs to be in play.
White Box includes Tolkienesque fantasy elves, dwarves and hobbits, kinda. Tolkien's elves are powerful creatures, especially the Noldor. The Third Age is the "Age of Men" and I personally prefer human PCs for gaming in the Third Age, but other referees may want to include the other races. The mixed race Fellowship in LotR is brought together by the actions of Gandalf and the Council of Elrond and seems out-of-character for the races to frequently do this (although it is the norm in default White Box play). I think diversity is more a modern value and medieval cultures such as Middle Earth is somewhat based on, would be more insular and xenophobic.
I have run two short campaigns in Middle Earth, one based around Arnor for which I drew heavily on Middle Earth Role Playing (MERP) material published by Iron Crown Enterprises (I.C.E.), the other based in Far and Near Harad for which there is far less canon and I felt I had more creative freedom. Both campaigns involved human PCs and redefined magic. I find that with cooperative players Middle Earth is highly playable as a milieu and a nice alternative to my home-brew campaign setting.