To be a little more insightful, perhaps, a TC doesn't use plugins to modify the existing Nova scenario. (edit: sniped by D.A.!) Instead they provide a completely new universe to explore, new ships and outfits, and new missions to take on. It's akin to making an entirely new game from scratch. It's certainly entirely possible for one person to make a TC, but you have to be dedicated to it thoroughly or you'll eventually lose interest and will have invested a lot of time for (probably) no reward.
When broken into component parts, there's not much that is actually really difficult. Graphics can be a pain if you're not skilled at them, and writing the countless descriptions, missions, and whatnot is going to be extremely tedious, especially if you have a large universe. The biggest threat to all TC's is the time involved, in my opinion. A great many people start off with a grand plan and then end up getting bogged down by a lot of little details, eventually losing interest and just not wanting to spend any more of their time on a fairly thankless task.
As far as EVNEW goes, it's an excellent program (and really your only choice on the Windows side of things). I would suggest starting with reading some of stickied topics in this forum, following the links where necessary, as well as familiarizing yourself with the Nova Bible (included in the Documents folder with your EV:N install). Then, if you're still unsure of what to do, download a few plugs from the add-ons page and open them up with EVNEW, look at what those authors did and just to go from there. Plug-in making always ends up more complicated than you think it should...this is only multiplied for TCs.
Still though, welcome to the Dev boards. New ideas are always welcome, and most of us will be glad to answer any specific questions you may have, as well give you the occasional helping hand.
This post has been edited by GutlessWonder : 14 December 2007 - 05:16 PM