I have a pre-64 264 Win mag "Featherweight" rifle which has a 22" factory barrel. It will push the 140 Bergers to about 3000 fps using Hodgdon Retumbo. Wear hearing protection, the muzzle pressure is over 18,000psi!. It has a flatter trajectory, less wind deflection, and more downrange energy than any of my other 6.5s. I think it would be acceptable for the hunting you describe.
I'm presently having a 28" 264WM Rem 700 fitted by Pac-Nor. It will be heavier and less portable than the old Win 70 but it should give over 200 fps higher velocity.