Crafting magical traps

[Sorceror]

Reading through the traps section on the PRD (http://paizo.com/pathfinderRPG/prd/ultimateCampaign/characterBackground/st oryFeats.html)
1) How does one build/cast a spell trap? "The appropriate spell descriptions explain the trigger conditions for traps that contain spell triggers." What spells have trigger conditions?
2) When using a Detect spell as a proximity trigger, does this count for the purposes of increasing the CR and DC? The tables say proximity triggers are +1 CR and +5 DC.
3) When using a Detect spell as a trigger, will it only trigger for detected events in the cone as described in the spell description, or can it be made to fit an area?

For general trapbuilding:
4) How much time does a Craft check take per day?

[DM_Blake]

1) The traps section talks about various triggers (proximity, sound, sight, etc.). This section lists several spells to use (clairaudience, arcane eye, etc.). Those spell descriptions explains the trigger (usually).

2) Yes. All proximity triggers, regardless of using magic or mechanical triggers, get these modifiers. There is no specific text anywhere in this section that says to treat them differently so they are the same.

3) I could argue this both ways and the RAW is not clear on it. Generally, when you use a spell to do something, you still must conform to the restrictions on the spell, so I would say that a Detect spell used as a trigger would still only affect its usual area, but you can put it anywhere. For example, if you want a trap to shoot darts out of a wall into a 10x10 square of a hallway, then put the Detect spell trigger on the ceiling aimed down - it would have a 60' cone right through the floor but you don't care, all you want is the square it's aimed at, and that's the only square where it will detect.

4) Figure out the trap's total cost from the Traps section, then use the info in the Craft skill to determine how long it takes based on the skill checks of the guy making the trap:

Find the item's price in silver pieces (1 gp = 10 sp).
Find the item's DC from the Traps rules.
Pay 1/3 of the item's price for the raw material cost.
Make an appropriate Craft check representing one week's worth of work. If the check succeeds, multiply your check result by the DC. If the result × the DC equals the price of the item in sp, then you have completed the item. (If the result × the DC equals double or triple the price of the item in silver pieces, then you've completed the task in one-half or one-third of the time. Other multiples of the DC reduce the time in the same manner.) If the result × the DC doesn't equal the price, then it represents the progress you've made this week. Record the result and make a new Craft check for the next week. Each week, you make more progress until your total reaches the price of the item in silver pieces.

[Sorceror]

DM_Blake wrote:

2) Yes. All proximity triggers, regardless of using magic or mechanical triggers, get these modifiers. There is no specific text anywhere in this section that says to treat them differently so they are the same.

Another look at the page shows the CR increase only in "Table: CR Modifiers for Mechanical Traps", so there's no CR increase for a proximity trigger on magical traps.

DM_Blake wrote:

4) Figure out the trap's total cost from the Traps section, then use the info in the Craft skill to determine how long it takes based on the skill checks of the guy making the trap

That much is clear, but the rules don't seem to say how long a single Craft check is expected to take per day, as in how many hours you have to allocate to it. I'm thinking, how would you fit it in between adventuring and the 8 hour rest? It doesn't just happen on its own.