Its impossible for me to overemphasize the impact the USDS can have, the question is never "will somoene let us do this" its always do we have the resources to do what needs to be done. What will crush you is the burden of service, and knowing the only thing limiting the impact you have is the amount of work you can physically put into it.

In terms of pay, I have kids and was a single income during my tour of duty. Its a better life then most Americans will live, so while your quality of life will not be as high as it may be on a private sector job, you won't be lacking anything you need.