You will be able to get answers from any security consultant or installer that does alot of jobs. As for the cabling you need a voice/data solution. to get the cat 5 or 6 those distances. You will need to put in patch panels or punchdown blocks. But you will not be able to certify the cables at those distances. you might want to consider fiber runs with break outs to copper.
I have worked with Endura systems that handle over 3000 cameras. It is written by Pelco so you can get help from them but you must be certified to buy, install, or get help on the equipment.