Adobe OnLocation is designed to do this, although it would need to be used in BootCamp. There are other applications that are Mac-native including ScopeBox and HD Monitor Pro.
Your main problem would be distance; a firewire cable can only extend for about 15 feet. If you need more distance than that you'd have to look into using firewire repeaters.
Using SD is the simpler option if it's just for a shot or two. I have run a 100' composite cable from the HVX with no problems. Firewire repeaters need power, which is a pain.
Obviously, you can't use it for focus, but you can use it for framing and check your focus pull when you bring the crane back down.
I'm a big fan of OnLocation on PC. It makes monitoring much more affordable. I have never been able to get a 2.5m cable to work in HD, though.