Just finished replacing the blend door on my wife's '97 expedition and it was as big a pain as I read. Much has been written on this subject but I thought I'd put in my two cents.
First... do your homework, there is a wealth of info on this site and some great vidoes on Youtube about the dash removal, or you may end up taking out many "imposible" screws unnecessarily.
Second... take your time so you don't end up breaking something or forgeting some screw or plug somewhere.
Third... have your wife or girlfriend help, an extra hand is nice for holding a light plus she can see how much work it really is which means brownie points for you plus you can count it as quality time spent together.