I use a Camranger and can't fault it. My camera is mounted 26m above me on the top of the mast and it works fine all the time.
As others have said it creates it own ad-hoc WiFi network, and once the details are stored in your Ipad (or whatever device) they will connect to it automatically according to the device preferences.
The device and the Ipad comunicate directly with each other, so notning else needed.
Screen refresh rate does decline the further away the device is, but it's still perfectly acceptable for relatively still subjects from 26m away. Obviously not much good for motorsports. For what you want to use it for, it wouldn't be an issue.
I did have one issue with it once, in a studio set up. It fired the camera (Eos 600D), but the studio flashes, which were fired from a hot shoe wireless transmitter, didn't fire. Don't know why, and to be honest, never bothered trying to find out why.
Search for it on Facebook and there's more comments from users on there.
I'd say go for it, I don't think you'll be disapointed.