By tube it looks like Southfields is the nearest about a 1500m walk from the station to the club.
www.tfl.gov.uk - Journey Planner says to go by tube you go Euston - Victoria (Victoria Line) - Southfields (District Line). Takes 40 minutes.
To Wimbledon mainline Victoria Line to Vauxhall and then Mainline from Vauhall
Vauxhall
Take the South West Trains towards Shepperton
or South West Trains towards Chessington South
or South West Trains towards Woking
or South West Trains towards Dorking
To Wimbledon. Takes 30 mins.
So if you take the coach to Vic, then you will either take the Vic line to Vauxhall or the District Line to Southfields.
If the train works you will have a gteed journey time, coaches from my limited experience have less reliable - or longer journey times.
If I was doing this it would be down to the journey time and how that links up with when play starts (or when you want to get there) and the best method for achiving that.