Hereford Station is under a ten minute walk away.
The best offer available at the moment, and can be bought at the station on the day of the game if you wish, is a £39.50 day return. (But four of you travelling together could half this to under twenty pounds, and less with travelcards, making this a great value day out in what was my trip of the year two seasons ago.)
However, going online directly to the train company involved will make sure you pick up any discounts on offer.
Examples
London Paddington 08.21 - Hereford 11.42 - £39.50 return
London Paddington 10.21 - Hereford 13.42 - £39.50 return
Hereford 19.11 - London Paddington 22.39 via Worcester Foregate Street
There are other services in both directions but these are the only ones, at the moment, you could use the First Great Western day return at that price.
For service information and how to book tickets go here: www.firstgreatwestern.co.uk
Give yourself over five & a half hours from Southend stations and at cost of £65.70 return, best to get a 6-zone day travelcard to London and then a day return from Paddington.
Station; top right, the blue blob; Edgar St. Stadium; bottom left via Commercial Road and above Blackfriars Street.
Hereford is in the Group Save area that can cut fares in half if four of you can travel together, and any various travelcards will make it even cheaper.
To find out more, go here:
www.daysoutguide.co.uk/groupsave.aspx