I'm still pending work schedule......so hopefully I'll see some of you folks, if I do.....I'll pop in towards the end of the week for a couple days.
Exactly. Fun fact, High Altitude Compensation would add 6 degrees starting at 4k ft. So bare minimum mark your line for 13* since you will be at 8k ft at the KOA and if you go up Imogene (which you definitely should/will), you'll peak at 13k ft. Your 3F likely has leaner jets at this moment (something like a 136/138 primary and 200/220 secondary) so once you bump your timing, feel free to use your choke to adjust.
Furthermore, since it's a 3F and likely a rest of world (ROW) truck, you should have a hand throttle. Using a mixture of choke and hand throttle will compensate for your needs (which is very dependent on engine vacuum). The closer to 22inHg at idle, at sea level, the better or off you are at high altitudes.
Last but not least....it's fun to bring a vac gauge, you can do some quick adjustments, otherwise a quick spin on the idle screw will be enough to bring idle speed up.