That puts them in Idaho, where the *bottom* of the valleys are at around 4,500', according to Google Maps. You can see convection off the peaks that would naturally produce a bit of sink between them but "due to warming temperatures we had a hard time gaining altitude" explains most of it.
4-up plus luggage at a density altitude probably 7-8,000+, being propelled by what sounds like a boggo 4-cyl Lyc., probably not leaned out. Ouch! I'm surprised it got into the air at all! Well, I suppose it didn't really...
Edit: It appears to be a Stinson 108 with a 165hp Franklin 6 cyl. That's a BIG ask at that weight and temperature.
Last edited by FullWings; 8th Aug 2012 at 17:39.