Well, sure, LAMP is easy to set up if you're working in PHP; that's one of the huge advantages PHP has over most other options. You want to set up and deploy to a Rails server, though, that's going to be a bit more effort.
I've actually had an easier time setting up Phusion Passenger with Apache than I've had setting up PHP. Ease of deployment isn't necessarily a major advantage in PHP's corner anymore.
Like Phil said, it doesn't take more than an hour if you're feeling lazy about it. I've automated it with Chef, but I haven't timed it or anything. Less than 10 minutes for sure.
Rails is not the difficult after you have done it a few times, just line up your console commands and get to work most of the time is waiting for stuff to download/compile.
