Did you buy extreme or regular? The front doors are pretty easy to work on. I put the biggest piece I could fit onto the spots of the outside skin I could reach being careful not to get anywhere close to window travel areas. Just peel back the vapour barrier where needed, apply, and then refix the vapour barrier overtop. Careful in the cold, the vapour barrier can tear if you aren't careful. Try to grab the butyl rubber seal through the vapour barrier when pulling so the seal comes off with the barrier rather than the vapour barrier coming off the seal. As for the inside skin, it was quite easy on the fronts to do a lot.
If you have lots left over, apply it to the inside of the trim panels too, they are quite squeeky.