I drive a cut-away, a clown bus (long body, short wheelbase) and full size conventional and flat nose buses at work. I've driven them all on the freeway.
Everyone of them get affected by trucks zooming by. In really windy conditions, the same thing. A big ol' wall for the air to push on.
If a bus can "safely" go 70 (no front end wobble, great breaks, plenty of maneuvering room (40' bus, 70mph, fast lane change or full on breaks) then go for it. Anything not in those parameters, save gas, wear and tear and enjoy the scenery.
Car vs Semi - https://trucksmart.udot.utah.gov/mot...ing-distances/
(semi 65mph - 525')
Class A Motor Home 40' - 50') - https://www.rv.net/forum/index.cfm/f...d/25559171.cfm
(65mph - 600', probably because they have less rubber on the road and less overall breaking)
This all assumes perfect road and driver conditions.