When I worked for various agencies in DC, one of the first things I learned was who the power players and key people were in each of our Senators' & Congresspersons' offices. It is quite often not the Senator but the scheduler. Yes, the person who runs the Senator's calendar and determines who gets on it and who doesn't.
We found pretty quickly that this scheduler was - almost without exception - a single woman in her mid 20's. Therefore, whenever we knew that we would need access, we would do little things like bring flowers or chocolates "for the office" but make sure to leave them with her. When we found out about new restaurants or a show she'd like, we'd pass her the info. By the time we needed that meeting and gave her a call, we would get it every single time.. often the same day.
And yes, we worked with both parties and names you'd recognize.
* Am I proud about any of that? Nope but that is how the Hill works. And giving those people more powerful is an awful idea.