We use an articulated stepladder similar to the one below to make an impromptu scaffold. We place a 10' 2 x 6 board across the top so that we can walk from one end to the other. A 2x8 might be more reassuring for you. The result is a very sturdy platform that is stable and strong enough for both myself and my wife. Ours is a cheap-ish Harbor Freight ladder, but any articulate ladder should work. We've used this setup without issue for about 20 years.
Werner M1-8-16 8'/16' mm Type I Aluminum Articulated Ladder