What's up with Thea users in the V-Ray forums trying to make converts of us?

There's absolutely no reason VR can't make a render using RT (in 2 min with a $1,000 graphics card) of a 30MB file with proxies.

Make sure you have the latest SP2.
Check your back faces - its good modeling practice
I would group some elements in your model - There's a lot of loose geometry, again its good modeling practice to use groups and layers.
Make all landscape into proxies
Render to EXR or VRIMG using Preview
Use the 64 bit workflow
If you have other machines on your network, setup DR