Make sure the scaffold can accommodate the front cab portion of the rv. Many scaffolds have a set of diagonal cross bars .
Have to tried to open the hood and carefully stand on the frame above the radiator ?
or.....Having a secure foundation to use a pair of ladders would be very easy.
If you could make two wooden plywood base-plates each about 4'x4' , lay them flat on the ground then drive the front wheels onto them, you would have a secure platform to mount a set of ladders. All weighed down by the rv.
Secure the ladders so they don't tip. Mount two legs of a 5' or 6' folding ladder to that plywood base by bolting two of the ladders legs to some short lengths of 2x4 that are bolted to the plywood near the outer edge of each front tire.
Just drill a hole through the 2x4 and ladder leg then pin it using something like a 1/4" safety pin. That would be quick n easy to assemble.
All you would then need is a 2x12 to run the width.
The ladders are still completely useful to use for whatever and the plywood bases can be stored flat not taking too much room.