If i really have that surprisingly bad day as suggested in the original post, just select any approach that does not require the ILS to be on the air in the FMC and fly it down to 100ft, at that point latest my autopilot will make me aware that i should switch it off (auto-callout AUTOPILOT) and gently float along the runway a 100ft if i dont switch it off. Of course it is not a precision approach, so with the weather described i really do have a problem there, i dont know if an Enhanced Vision System as you can get on business jets would help there, sadly boeing still hasn't managed to certify it on the 737 although they announced it allready in 2002 or so.
If there is a military airfield nearby try to land there, many of them still have GCA equipment and trained ATCOs and they can talk you down until you hit the runway.