Hi Dave, My understanding about seasoning is that only bare metal has to be seasoned and the WSM is painted throughout thus it doesn't need it. As far as the black stuff, it sounds like food grease and since I only have a couple of cooks on my WSM, don't know how to deal with it. I'm sure others will reply - One Mr. Mom to another!
Never had anything dripping from the top, I get black stuff that looks like ash coming down once in awhile. It is can be cleaning with some simple green or hit it with a power washer once in awhile if you have one handy.
What you're experiencing is normal. The color and consistency will vary depending on the meat and wood you're using.
After you close all the vents to shut down the cooker, while the WSM is still warm just take a wad of paper towel and wipe the edge of the lid and the lip inside the cooking section where the lid rests. You'll have no sticking of the lid after the cooker cools.
I find the condensation more an issue at the start than at any other time. An orange based degreaser will remove it with a tire brush and a garden hose. A Karcher pressure washer with a dirt blaster nozzle from Costco is an awesome piece of equipment. I just got one and have been cleaning everything in sight with great success /infopop/emoticons/icon_biggrin.gif
~Konrad