I'm really surprised by the point to shoot outside. I suppose that could cut down lighting costs, but you lose so much control outside that it seems it would be counterproductive.

As noted, you have to pick a location where there is lots of sunshine, little rain. She mentioned northern New Mexico as being ideal, a place she had used a number of times for various productions.

Night scenes can drive up costs, especially if you have them spread over several locations. Crew get turnaround days (paid, nonworking hours) to compensate for sleep disruption going in and going out of night shoots. If the night scenes are in several locations you often can't do them all at once, so you're paying for several days of no work. The most interesting advice given to me by a Line Producer regarding cost was "the more specific, the more expensive". So if I write a scene on a roof he can get the cheapest roof possible. If it's a roof looking down on a city, his choices are more limited, and it's less likely he'll find one that can do a deal. If it's a roof looking down at a city with a helicopter pad on top there may only be one in the whole district, and he's gonna have to pay whatever the location wants.

I think the best advice to beginning writers is to be prepared to change or cut anything the producer asks of you. There are things in my current project that I had no idea affected the budget. Albeit, I'm on my first real screen project, but man... Set that ego aside.