It would definitely be a help to remove the downspouts, and shouldn't be too difficult, as little as popping some drives or removing some screws. The gutters are a different story, and would depend on what type of gutter and mounting system, what type of design they're mounted to, and how bad the work area is that they are blocking. It probably wouldn't need to be or even be feasible, as some systems would be damaged in removal, like K gutters with spikes and ferrules. Although, especially with half rounds, I've cursed them many times and wished removal was an option. All that said, I have worked jobs where the gutters were removed to paint, because you just couldn't do the job properly with them in place and it cost less to remove and reinstall than to work around them.