I personally think that a max. density alt. of 7000 ft is low, the plane surely must be able to do higher?
JeroenC, I don't know exactly where you'll be flying but consider Jackson Hole, Wyoming. 6500 ft elevation and 6300 ft long. Density height, say, 8500 ft. In a Cessna 172 for a local flight. The POH showed that the runway length was more than adequate and that the rate of climb was OK - I was not extrapolating in this case (and I am, or was, a flight performance engineer). I'd flown the aeroplane several times recently, slightly lower weight though. Light wind. After take-off the modest climb rate became a steady descent when a slight wind shear occured due local terrain - a little canyon was funneling the wind. I was within seconds of setting up for a landing in a field. Eventually got it up to 11,000 ft - the minimum needed to go somewhere.
I much preferred the Husky - it'd go straight to 12,000 ft with no doubts. In that part of the world 12,000 ft is normally where I'd cruise, with the occasional step up to 14,000 to clear a ridge.