Making the party roleplay through everyday activities in all but the simplest of methods is a potential disaster, risking a mutiny due to boredom. But without at least an element of the routine, the fantastic becomes mundane, as the party of murderhobos slides along from encounter to encounter like an old fashioned FPS game protagonist. How do you split the difference?
I've tried a number of things. I like to request my players use a forum or blog post to lay out how they use their downtime. Non-spur-of-the-moment shopping (particularly shopping for unusual things or where they don't know what they want) is to be done not during play. But how to make them take this seriously, and really immerse themselves in the world?
Give the party a morale counter. Every player has morale points equal to their willpower. Morale points are lost whenever the player experiences trauma, or just as a function of fatigue. Points are regained through leisure. Drink with friends, tell scary stories or sing around the campfire, watch some enjoyable programming, enjoy a hobby, getting a good night's rest, etc. This needn't be roleplayed extensively, just sufficiently to establish that the character actually exists outside of adventuring.
Morale Point Costs:
Making a Fright Check, 1 point; Cannot lose more than half morale to passed fright checks
Failing a Fright Check, 1-3 additional points; Degree of trauma (failure) determines point cost.
Performing questionable actions by the character's morals; 1-5 points for degree
Long or boring tasks, 1-2 points.
Extended periods without downtime; at Will-(days since last rest) days, begin making will rolls to maintain morale. Each subsequent roll is at -1, 1 point lost upon failure.
Substantial loss, 3-10 points.
Effects of low morale:
Half Morale: Below half, the character is fatigued. This may take many forms, depending on their personality, but there is always a sense of malaise. It would be wise to rest.
Below 3 Morale: Depression. Use the rules given under Chronic Depression (B126)
Negative Morale: Below 0 morale, rolls to resist depression are at a penalty equal to how negative your points are. At -1X(Will), make a will roll to resist becoming suicidal.
EDITS TO COME: adjusting rate of morale loss (likely a modified will roll), and the effects certain advantages have on losing, gaining, and maintaining morale.