Home owner cleaning solutions?

[Aflavin 0]

Hello everyone, I'm new to the forum and have been reading a lot. Tons of great information here. I just bought a new home late last summer and it' now time for spring cleaning! I have a lot of washing that needs to be done. If ever, it' been years since it has been cleaned. I do intend to hire a professional to do the siding and roof so I don't damage anything and spend more than I could save. The biggest project I have to tackle is a lot of concrete. I have a large drive way, some sidewalks and a pool deck. The staining I see now is all a black residue. I intend to go to my local big box home store and purchase a "decent" gas power washer that advertises 3000psi. I've cleaned more than a few driveways and decks and fences in the past but would like any possible advantage with the size of this job. I have a few questions if anyone has a few minutes to offer a little guidance. 

1  can anyone recommend a cleaning agent that will help,  and dare I say be used on more than one surface? I do have access to some decent quality industrial degreasers but I don't think they're what I need for my application. I don' have oil spots just some staining. I'll post pictures if they help. 

2 Is it worth purchasing one of those large round rotating surface cleaners? I have never used one or seen the results they can provide. I would hate to buy a piece of equipment that's more of an advertising gimmick than functional tool. 

3 Does anyone know a contractor in the West KY area?