How long does HIV live outside the body on surfaces and does it matter if the environment is wet or dry? What special cleaning/precautions can I take in the home setting to minimize risk to neg family members?

I don't think there is a precise answer, and my educated guess is that HIV doesn't survive long at all, regardless of whether the surface is wet or dry. If you are talking about cleaning up fluid that is bloody, then a 10% bleach solution (1 part bleach to 9 parts water) will kill any HIV virus on contact. If you are talking about the everyday mess that all of us make (crumbs on the table and floor, dirty clothes on the floor, etc), then no special precautions need to be taken-- HIV just isn't spread in those ways.