About 1.2 miles 'as the crow flies' but the shortest route I can find is 1.5 miles but that includes the muddy embankment behind Vermillion. Looks closer to 1.7 miles for a safer route but it shows that if they addressed some of the barriers for pedestrians the various routes could be shorter. Still too far to be attractive though. When the proposal for Sandhills Metrolink interchange came out, they talked about trying to get tram stops around a maximum 800metre distance for the majority of residents in the area (that's 1/2 mile or 2 minutes for Steve & Seb), mainly for a commuting perspective. So for occasional users like us and arena goers I think double that distance should be the top.
Sandhills (if it is still happening) will be about 1.2 miles by crow as well so although good for the Bury line users (0.5 mile nearer than Victoria), it is not much of an improvement than Central Park. In short, there isn't going to be any new tram or train stop inside a 1 mile walk until a stop is built on the line that runs behind the athletics stadium.
Pretty depressing, really.