If you try to fly one of those RC blimps outdoors in anything but the most absolute dead calm days, you'll lose it. Wind picks up dramatically as you gain altitude. That 4000 ft stuff is talking about high elevation air pressure differences, not flying that high above ground level. Take it from me, I am an engineering grad student who works with UAVs and I've flown tethered weather balloons and kites for aerial photography, its a pain in the ass to carry any decent weight and you're not going to get good footage without putting a pan tilt unit on the blimp and controlling that with RC too. You have to carry the weight of the radio transmitter, camera, servos, and a battery. And control the blimp in wind. Its not easy, though there are commercially available blimps for this purpose for thousands of dollars.
I personally have more experience with RC helicopters, which would work well for this except you need a very skilled pilot and a heli that'll cost at least a couple grand.