If you're getting yard signs done, order them NOW.
Most local printers who offer yard signs don't actually have the equipment to print yard signs. Instead they outsource to a handful of companies specializing in yard signs, particularly using one in Tennessee and another in Florida. While this isn't a problem most of the time, Halloween signs suffer from the political campaigning backlog, which was particularly bad last year. I went to place my sign order last August only to find out I likely wouldn't get the signs before Halloween, let alone in time for the event on the 26th.
Vinyl banners, on the other hand, you should be able to source from local printers with the right equipment as little as 2 weeks before the event.
My next tip is: your expectations are a bit wild. It takes a few years to build up a reputation for a haunt. My first year was less than 30 guests and the second was 5 times that. This year I'd be looking at as many as 750 guests had my volunteers quit on me a couple weeks back. So try to lock in a three or five year arrangement for the tennis court, and don't get disheartened if you don't hit that 1k mark on the guest count.