Ford Repair: towing / engine, ford conversion van, head gasket

Question
hi, have 1990  E-150 ford conversion van with a 5.8. And it has 166,000 miles on it. Thinking of going to florida with it for the second time,And picking up a 3000 lbs rv and towing it back to nj.I do maintaine this van well. just last week i put new plugs in it and found that # 5 cylinder plug had a redich substance on tip of it. What can this be? and do you think i can get 300,000 miles on the 5.8 if i take care of it? IS TOWING 3,000 LBS OK WITH THIS VAN. its an old van, put i really like it allot can not let go.
                 thanks
                  RAY  

Answer
Hello and thanks for the question...I'll try to help.
With out seeing or knowing the van itself....I can't say. YOU are the best judge of what the vehicle can or can't do. As far as what's on the plug.....have you had to add coolant to it lately? Could it be the start of a head gasket leaking?
Erik