Be careful not too make it too realistic, you may get government agents thinking you’re planning a terrorist attack
Anyway good to see some interest still in the game.
A lot of topics are covered on the editing wiki which I’m sure you know about if able to make megatextures but here it is just in case, http://wiki.splashdamage.com/index.php/Enemy_Territory:_QUAKE_Wars
Before you get carried away I suggest you read up on the optimisation related subjects, batches, texturesheets, LOD groups, detail groups and portals. Knowing these now will save you a lot of trouble later, I wish I knew more about them when making my first map in ET:QW, had bad fps and was too big of a task to fix.
For scripting objectives and such I just use the stock maps as a guide, I think all stock maps have a reference map file for the objectives so you can look at the entities used and how they tie in with the script. It’s a real pain to get it working at first, you have to set up all sorts of files for the game to read your map script correctly. Might be best to try and replicate some objectives in a basic map to get a feel for it.
The SDK test map gives a nice example for how territories are setup, however this isn’t required to have working objectives, it just used for deployables and vehicle spawning, it’s generally one of last things I do along with command map. one thing to note about the sdk test map, it uses a broken method of generating heightmaps and path finder nodes for magog/deployables from memory, the wiki is also wrong on that subject. When you come to this make a topic and we’ll try help you out.
ET:QW can deal with .ase .obj .lwo and also uses .md5 for animated models. I typically use .ase, seem to have more luck with that, especially with terrains. I make most of my geometry using BSP in editor though as it’s what I’m more comfortable with.
Anyway good luck.