Manchester United Game from London?

I think you could do it in a day on the train. There is a Metro station at the ground. The fan's guide explains how.
http://www.footballgroundguide.com/leagues/england/premier-league/old-trafford-manchester-united.html#aby-train-and-metrolink

What you should be aware of is the fluidity of kick off times. A game between United and Chelsea is almost certain to be moved suit television schedules and it won't be announced until nearer December if this is to happen. If your son is a Chelsea fan perhaps you ought to aim for tickets in the Chelsea section of the ground although you would probably need to contact Chelsea to obtain them. Tickets for this game will be in very high demand.

Hmmmm...good to know about the TV time, and that makes sense. Is there a pub in London where fans would typically gather to watch? That may be a more convenient option.

Be aware that Man U v Chelsea is a huge rivalry, and tickets will be very scarce and very expensive; Super Bowl expensive:(

Your best bet to secure tickets will be via resale sites like these:

http://tinyurl.com/ok3dkan

http://tinyurl.com/nbdkcgz

Currently only VIP hospitality ticket are available. As it get closer to December tickets for the regular stands will become available.

Lots of pubs and sports bars will show the match but maybe you should look at alternative match in London if you decide not to pursue the Manchester option.

Arsenal play Bournemouth . Best ground in London plus playing Bournemouth is a tiny club making a romantic first season (probably only season) in the top division.

Crystal Palace play Swansea . Two mid table but very attractive sides.

West Ham versus Southampton . West Ham playing their last season in their old East End home before moving to Olympic Stadium against the team I support who have been very good the last few seasons.

All these are games worth watching live and perhaps a better bet than trolling all the way to Manchester despite the "glamour" of the fixture. By the way Chelsea have been pretty poor at the start of the season although I fear that may change.

The week between Christmas and New Year is typically when a lot of major engineering projects take place on the railways. I haven't checked - it is a bit early yet for all that to be announced - but it is worth keeping that in the back of your mind.

Also - that date, the 28th, is a bank holiday in England. Because of the weekend, that is Boxing Day. Usually there are no tubes, buses, or trains on Christmas Day, and no or virtually no trains on Boxing Day. It is really worthwhile double checking transportation on trains, especially going as far as Manchester, for that day, And in and around London over the week.

What would be a good pub for Chelsea fans?