Trapper questions

I am new to rangers, currently I have a warrior and he's doing fine. I want to build this trapper for farming it seems to me they can kill lots of enemies in UW. My questions are as follows:

1-Which campaign is it better to start a trapper? I currently have the 3 campaigns, I would like to avoid Prophecies since I am already running it with my warrior and it would be repetitive.

2- I noticed that some good traps like "Dust Trap" is only offered in Prophecies it it possible to get it in other campaigns or what to do in that case?

3- I was thinking of a R/Mesmer because of the Echo and Arcane Echo skills since it will benefit alot.

4-How can a trapper support a party in the case that you need to party up?

5 - How does a trapper do in open spaces?

Any tips and advice on trapping would be greatly appreciated.

Thx..

1 - i don't think it really matters, i like prophecies because you can get a lot of free skills that way

2 - you can only get it in prophecies, but if you have the skills unlocked already then you can get it at the bal temple...i think.

3 - that's a good idea.

4 - usually, if you are doing PvE, then you don't play as a trapper. it would probably make the party run slower, because then you'd have to pull them and make them come to you and stuff. because you can change your builds, you don't have to go as a trapper, so you might think about going as something else. a trapper is mainly for farming, in which case you don't have to party up with anyone because you can go with yourself if you'd like.

oh, here's something, if you wanted to read about it
http://gw.gamewikis.org/wiki/General_trapping_guide

thanks for the advice and the link Little Shenanigan. I can always use the bow when in parties and change my skills in towns and outposts.

There are PvE trapping builds, they tend to be more aggressive and less concerned with laying rows of traps, and either use an Oath Shot to maintain defenses or Trapper's Resolve to trap without interruptions (though other builds work too).

Oath Shot trapping was very standard for maintaining Whirling Defense while trapping in the old days, Trapper's Resolve works pretty well too.