So if you like come across a vampire's coffin and oil down the place and light it up it won't do him no damage at all?
Although I don't think these rules it specifically say, I have always played Vampires this way. If you kill them they turn into a gas and get pulled back to their coffin. Once inside they regenerate, thus if they have a coffin they can't be totally killed. I have known GM's to give Vampires multiple coffins, so that even if you destroy one coffin there is a good chance another is hidden somewhere else.
If its one thing I got from these posts is you have to check with the GM first before you go running off to like try and kill a vampire. Make sure you know what the GM says can kill it.
They have 2 hours to reach the coffin, they can cover 9 miles in that time altho I'm pretty sure wind speed effects gaseous forms travel speed. If they don't make it they are destroyed. Once in the coffin they are helpless for the 1st hour. Catch it while it is helpless and its easy to destroy.
Sending it back to its coffin is the hard bit. Like it was said before if your prepared it can be done otherwise your in alot of trouble.
You have to remember a Vampires smart. He is going to have guards and traps around the areas where he/she keeps their coffins. A wise vampire always has more than one coffin and a prepared GM should play the vampire smartly. Who says the vampire is not going to secretly approach the party when it feels it has the advantage. Charm one or two of the party and you now have to fight each other as well as the vampire. Even for higher levels a vampire can pose great risk.
Its always fun to find out one of you'r most trusted NPCs Is a extremely evil Vampire,
While the book says its easy to spot a vampire Ive always found a few simple spells and the disguise skill should suffice enough that you don't have to change any rules.
Vampires also have turn resistance so they are harder to turn than most undead.