In reply to Mike Knudsen, the two easily accessible places 
you might visit are St Albans Organ Theatre in Hertfordshire
http://www.stalbansorgantheatre.org.uk/  and the Musical Museum 
at Brentford in South West London http://www.musicalmuseum.co.uk/

It is the Musical Museum which recently slightly relocated, not 
the St. Albans museum, which is now known as St Albans Organ Theatre,
but remains in the same location.  The web sites of both these places
correctly show their current opening times.

The Brentford museum is located very close to Syon Lane Station. 
The St Albans Theatre is about 20 minutes walk from St Albans Station
(not to be confused with St Albans Abbey Station which is not well
located for the Theatre), heading away from the city centre, but 
taxis are available from the station.

As far as getting around by train goes, simply use the site
http://www.nationalrail.co.uk/  The "Journey Planner" facility will 
tell you train times, fares and all you need to know.  This takes 
into account any engineering works which may cause train schedules to
be altered (or use of a replacement bus for part of the journey; this 
is not uncommon at weekends).  

Where a journey crosses London, the fares quoted are inclusive of
travel on London Underground (or the "Thameslink" service which runs
north-south across London and is helpful in making certain journeys),
which connects all the main line terminal stations and is not difficult
to use.

Of course, if you prefer, you could take a taxi to cross London, 
but you would have to pay the fare.

Hope this helps, 
Peter Craig