ruebensmurphy-
I'm not bashing the R-66, but you really should consider the Enstrom for high altitude flying. If you feel the need for turbine power, the 480B is an alternate to the R-66. If you're comfortable with a piston engine, you'll save a lot of money going with a 280FX or F28.
I agree with chopjock- flying in the mountains or anywhere with potential turbulence, a fully articulated rotor head is a better choice. (Now hunkering down for the inevitable storm of controversy...)