Need some help with structure

[Takeoffyouhoser]

I am making a SP map which starts off in a swampy area like Yavin before going underground. I have a few questions to ask to help speed up my building time

[Takeoffyouhoser]

i hit the damn enter button by mistake... here are my questions

 

!) How would i go about making the canyone face. Do i use brushes then use the E and V key, or, can you use patch meshes.

 

2) also, since this is a narrow, snaking canyon, do i make one big bounding box and build inside it, or do i connect each leg together?

 

thanks..