Tough Referee Decisions

Are you ready for the hard questions?
OK, you think you are ready to run your first dungeon. You bought the White Box, deciphered the rules, chose a combat system, decided how to handle combat initiative (if any), assembled your dice and invited your players. Your map is drawn and you have included traps to trip-up the unwary, puzzles to puzzle the brightest, monster encounters both dangerous and entertaining. You have wandering monster tables, hidden treasures and you are ready for adventure. Basically that's true and many an evening's fun was had that started just this way. Tough decisions? Don't be discouraged, oh referee. After all, you are god within your own dungeon!
Have you thought about character death? How cheap is PC life in your dungeon? Suspense depends on a certain amount of player concern for the life of their paper avatar, but discouragement awaits the player who seems to always be the first to die. Is death permanent, or is resurrection readily available? Losing a higher level (what that is depends on the campaign) PC that has been adventuring for some months can be disruptive not only to the player of said PC, but to the campaign as a 1st level character now takes the dead PCs place. How does the referee balance things for a 1st level PC a midst a group of higher levels?
What happens when the lights go out? To players who all know what it's like to not be able to see, that is a scary thought, unless you can see in the dark. If you can, just blink a couple times to help your eyes adjust and yeah, things become clear again. Except for the players without the ability who are still just "in the dark". In the LBBs there is something about all monsters (any being not a PC) found in the dungeon can see in the dark unless being controlled by the players, or something similar (nrh). So an ogre can see in the dark right up to the moment you hit him with a charm spell and failing his save comes under the control of a player. Then the ogre is unable to see in the dark. I think the point of this is being in the dark is scary to players and that's a good thing for the game.
All players seek treasure and desire magic items, but how much to award them, that is the referee's dilemma. In White Box experience is tied to treasure and therefore players are motivated to acquire coin in order to level-up and be successful adventurers. Magic items are a fast-track to becoming more powerful and are therefore valued above their monetary value. Are there magic items for sale or do they have to be found while adventuring? Magic items can vary considerably in the power they grant to the PC and may unbalance planned encounters, but also make that PC much more effective than other PCs of similar level. Accidents happen and sometimes that too-powerful magic item gets into play. One of the tough challenges for the referee is how to handle that situation.
Balance is not directly talked about in the LBBs (iirc) and the idea of balancing challenges and encounters is a later edition concept. That said, referees do try to present players with a mix of challenges, some fairly easy, some hard, but achievable, and others which need to wait until PC abilities/levels increase. The LBB concept of the dungeon level and listing the monsters likely to appear on each level is an effort to let the players have some idea what level of challenge they are likely to be encountering. The idea obviously is that deeper levels have more powerful challenges/monsters and correspondingly more valuable treasures. Applying this mechanic to the wilderness adventure is a bit more challenging for the referee.
"What does my character do when he is not adventuring?" The time in between adventures or "down time" can be as important or not as you, the referee chooses.  In the LBBs there is referee advice to keep good track of time in the campaign. This makes sense if down time is important. Some referees require training in order for a PC to advance in level. In between adventures (maybe over winter if your campaign includes seasons) is a good occasion for this training to occur, if a mentor or trainer is available and if the appropriate amount of game time passes before the next adventure. One way to influence how much wealth the PCs have accumulated is life style costs and training. Spells may need to be researched and this takes time and money. Down time activities such as finding an appropriate mentor or teacher can become it's own adventure, if that is the way the referee wants to run things. How much "realism" do you and your players desire?
How to handle offspring and inheritance when the question arises, which is likely to happen especially in an immersive campaign with a fairly high realism factor. Players will want to bank some of their excess wealth and may even attain a status allowing them to own property and acquire titles. How much does my new PC, son/daughter of my old PC inherit is a question the referee may face. Allowing for multi-generational play, if incorporated into the campaign well, could presumably add yet another layer of realism and fun to the campaign.
Or you could go back to the beginning of this post and just run that one-off dungeon. My first campaign was a series of one off dungeons.  The only thing that could be considered campaign-like about it was many of the adventures started in the same tavern and they involved the same PCs who leveled up occasionally in between adventures. It is truly impossible to anticipate and plan for all the tough situations the referee will have to handle, so you may ask "why bother?" I will be the first to say, there's nothing wrong with just "flying by the seat of your referee pants!" After all it's just a game, have fun!