At the very least, he can relocate them to logical locales. Interior in Denver, say, Agriculture in Omaha, Commerce in New York, making those agencies closer and more responsive to the people they're supposed to be serving. And also energizing the economies in those places. It's ridiculous that an ever-more corrupt "District" of 600,000 people holds sway over the entire country, just as ridiculous as our "representatives" having to trot off to Washington like it's 1789 or something when they could do 90 percent or more of their work staying put in their home states. Admittedly, that would be a big blow to Washington's bartenders and prostitutes, but they'll likely survive.
A businessman like Trump sees Washington as the completely outmoded, antiquated monopoly it is. And that's why its denizens hate and fear him.
I agree, representative should spend more time with the people they represent. Most of what they do can be handled through a Zoom call. It would also keep them far away from lobbiests. They could meet in DC on a scheduled basis
Having agencies closer to who they represent would also be helpful.