Jack,
Check this link for access to the front drain tubes for the sunroof. It shows it in pictures. The glovebox needs to be removed which isn't a big job to simplify things on the passengers side.
http://www.btinternet.com/~weird_world/IMG_1925.jpg
Now the "A" pillar covers; got me on the right day as I've just finished removing & refitting as I have just had a full mobile phone kit fitted to my BX 16V.
Firstly, pull the top of the A pillar straight outwards; carefully but firmly. A white "Christmas tree clip" will come out & *may* bring an opaque pipe clamp with two holes in it with it.
Then move to the centre of the pillar and with the top held slightly outwards, do another direct pull there also; this should reveal the same thing again. Pull the cover upwards towards the roof as the third one is the same as the other two but whereas the top two were held in place by keyhole slots pointing upwards, the bottom one points downwards so the cover will come off without the clip having to be removed. I used double sided tape to stick the drain & anything else that is floating around to the actual steel of the A pillar.
Now, in the famous words of one Mr Haynes Esq. refitting is the reversal of removal; but with a bit of a difference!
Firstly pull those opaque pipe ties off the christmas tree clips. This is MOST IMPORTANT as you cannot refit them where they are. Fit these firmly in the holes provided (be careful with the top one as there are two holes there so be sure to line the correct one up first) this usually entails using a screwdriver to squeeze them in to ensure they are fitted properly; you'll know when they are in as they should be, as they will actually be hard to remove; if they feel as though they are just sitting there, they aren't in right. Then grab the can of silicone spray and at the bottom of the A pillar cover is a piece of black rubber slid across the botton; give it a spray before you start. Get outside the car & looking through the windscreen, slide the bottom clip into the keyhole slot on the cover. You may have to use a slight bit of pressure on the bottom to get it into its slot between the dash & screen but with the silicone spray, this is quite easy. Spray the tips only of the christmas tree clips before you start.
Then again from outside, line up the centre one and when lined up, push it in repeating the dose with the top one. Just use the ball of the palm of your hand to run down the A pillar cover to be sure the clips are pressed home and it's all done.
Can be a scarey job but done as I say, really quite a simple task.
Hope that is some help,
Alan S