For the window channels and such its actually pretty easy. Just takes time. Depending on how much rust is there is going to determine replacing or fixing whats there. If theres just some pin holes, welding really doesnt work so well because the metal is so thin and usually burns through, I heard of people using a two part expoxy putty. But if the section needs to be replaced , find a parts car in a junk ayrd , etc. IF you can't find one go to a local body shop and look through their sheet metal piles. You will find many pieces that have bends/ channels that you can use for a patch for the area you need. Hope this helps. Nick