In the early 1970s I was attending the same high school where both Bush's went. Quite a few students including (I admit) me went to a demonstration in Washington. We travelled by bus. Nobody paid for the bus or our other expenses except us. There were hundreds of thousands of people there, more people than I have ever seen in one place in my life. Nobody paid for all those people to be there.
There was indeed a stage and loudspeakers on the capitol steps and the money for them must have come from somewhere. But there were so many people against the war who weren't communists who would have been willing to donate to this cause that any Russian funding would have been superfluous and counterproductive from a Russian standpoint. Despite the intensive COINTELPRO program, the FBI never seemed to find any KGB link to the demonstrators. If there was any Russian funding it was an unnecessary drop in the bucket. If you have some well-researched historical information to the contrary, post some links.