Chinook the best large helicopter? I think not
It may have a good load fraction but would you really want to put your President in one that often?
Chinook (or rather the BV234 derivative) was busted out of the civil pax market by a combination of vibration, awkward costs and awkward secondary safety issues. Knut Lande showed me round one at Helikopter Service and I couldn't believe the leaks, awkward access panels, tiny emergency exits and large damping masses needed. You could add deep carpets and curtains, but remember all those Sarah Palin lipstick jokes ...
This is an aircraft for hard men, not a regular ride for heads of state.