Mold remediation in crawlspace
I've found some good guides about this, so I'll share them here. I won't be accepting this answer, so if anyone else has something to add, please do.

The US EPA publishes a guide on mold remediation in commercial buildings, much of which seems applicable to residential buildings also. The guide recommends three methods to clean wood surfaces smaller than 100 square feet: wet vacuum if the area is still wet, damp wipe with detergent, and HEPA vacuum when dry.

The guide also provides advice on what protective equipment is required for cleanups of varying sizes.

The Washington State Department of Health publishes a guide that provides much of the same information as the EPA guide, but has an additional recommendation about treating surfaces with a cleaner containing borate to inhibit future mold growth.

Any remediation activities should be performed after the source of moisture is identified and removed.

I suppose the best advice is probably to consult a reputable remediation professional, as molds are allergenic and some are toxic, even after they are dead. The resources I've found suggest hiring a pro for cleanups of any area larger than 10 square feet. If performing the remediation yourself, take all necessary precautions to protect your health and to limit exposure to building occupants, and of course don't rely solely on this answer for advice.