[Disengage lurker mode]
Apologies for the length of this post, but a 4e sandbox campaign has been on my mind a lot in the past few months.
I was involved with a very lengthy and epic 2e campaign, that started with pre-written adventures and moved into a sandbox type game after about 10th level. The whole group had a blast and agreed that the sandbox style encouraged better roleplaying and more player involvement. The storytelling duty felt more evenly spread among the players, rather than it being incumbent on the DM to do everything.
We were intent on continuing it with third edition but found that 3e was too difficult to run in sandbox style, as there was less hand-waving and monster encounters needed a lot more consideration.
So with 4e, I'm excited to jump back into a sandbox game, and have spent the past few months fleshing out an area the PCs will play in.
Not to bore you with petty details of my own campaign, but I thought I might impart some of my ideas, particularly the idea of quest cards, which I saw in some official WotC document, (
http://www.wizards.com/default.asp?x=dnd/drdd/20071121 ).
So anyway, the PCs are starting out on a sort of post apocalyptic world, where something has entirely disrupted the nature of things. Empires have fallen, monsters are everywhere, the nature of magic has changed, points of light, blah blah blah. The PCs hear of a secluded valley where the monsters are kept at bay by some ancient and mysterious means. Naturally they go to check it out.
Heading into the valley, the need to go through a cave, in which they'll be jumped by some "horned creatures" (kobolds). The PCs have their first fight and go through the cave, only to find that the kobolds had recently waylaid a merchant and his guards. The merchant is alive but the guards are dead. This is where the quest cards come into play. Basically the idea is I give the PCs some cards that have quest details on it, along with some colour coding to define threat and urgency. I used the Magic Set generator program I found in this thread (
http://www.enworld.org/showthread.php?t=220953), and adapted it to make my quest cards, which I've attached.
The idea is to have a reminder of things to be done in the valley, then, when they complete the quest, I can write an XP reward at the bottom and they can file it away. The idea is that they'll always have at least one or two unresolved quest cards, so they won't run out of things to do.