Going to D.C. would be a really dumb, and expensive move. They could accomplish the same thing by simply parking wherever they are at the appointed time. That was done by teamsters in the 1970s, I remember them doing it but don’t remember the outcome. I know the teamsters back East not only parked they would not let any trucker move his truck and used violence to make it work. A friend of mine had a fairly new rig then with a big payment and he got stuck somewhere back East, couldn’t move his rig because of union thugs. Things are more just in time now so it would likely be more effective if a shutdown was done now than it was then.
Michael Savage proposed something similar some time back. If all the truckers stopped on the roads and bridges across the country, throwing out signs to express their outrage at illegal immigration / confiscatory taxes / socialism, it would be too big and widespread for the media to ignore and the public to NOT see.