Slow down and drive what's comfortable to you within the speed limit. You are going to have some vibration. The tires are like a rocks compared to a car and a lot closer to each other so you get a lot more rock that after a while you do not notice. I'm at a lost to why someone has the urge to exceed the speed limit as much as they say. That's reckless driving in VA. Drive what society has made a law to do and enjoy you bike. Driving reckless is killing innocent people. At 100mph on a public highway makes you a terrorist with a 700+ pound hand held missile. Grow up.
Just my opinion but I live it.
Around here in NorCal, the speed limit might be 65, but thats a laugh. If you're not doing 75 they're goin over the top of you (and thats the slow lane)
I run my 88/5sp btwn 70 & 80 all day. Vibes are minimal. Not as smooth as a tourer, but pretty smooth (just the previously mentioned handlebar buzz- comes in around 72-74 mph, but goes away just above 75)
I do prefer back roads, but all but one, Ya have to take freeways to get to.