This is how I'm doing it tonight -- a spin on 3rd Edition's search rules.
Party has one chance per turn (10 minutes) to locate secret door or find hidden object.
Search Difficulty (SD) represents how well the object of the search is hidden:
DM rolls a d24 and adds...
- SD20: Object is easily located
- SD25: Object is somewhat difficult to find
- SD30: Object is expertly concealed
- SD40: Object is practically or literally invisible
1) Level of most experienced party member involved in search.
2) INT adjustments of all party members involved in search.
Result must equal or exceed Search Difficulty.