Thanks Beancounter, I've looked at the links and PM'ed you. Since then, rooting around I've come across this, excerpted from COPA's "places to fly", this is Chilco lodge strip, a bit N and W of where I expect to land.
FLIGHT PLANNING
To access Ts?yl-os Park/ Chilko Lake by air takes some pre-flight planning. The importance of proper training, procedures, and pre-flight planning when flying in this remote mountainous region cannot be over emphasized. In the Pacific area, the combined effect of the great Coast Mountain system and the adjacent Pacific Ocean leads to extremely changeable weather conditions with an unpredictable variety of patterns.
When operating in mountains, factors such as density altitude, turbulence, and wind effect must be considered, as they will affect aircraft performance.
Another consideration in planning flight operations into remote areas (

Vancouver VNC AIR 5004

May 00 is the one to use for this flight) is that "Sparsely Settled Area" is no longer a defined area. As such, the pilot/operator must decide what survival equipment is to be carried on board the aircraft in accordance with regulations
As you suggested, I am planning an inland route, flying North from Washington, clearing customs and topping tanks in Penticton or Kelowna, then flying the east edge of the mtns until nearing my destination east of Chilco lake.