I found that your question was not as straightforward as I thought it was at first.
For much of the day there is an hourly service from London Euston to
Manchester Piccadilly that takes 2h11m, and there are other services
that take around 2h19m. In the other direction the corresponding times
are 2h13m and 2h23m. In theory, therefore, one just needs to live
somewhere along this line, just on the London side of midway.
The catch is that most of the fastest trains don't stop much in the
middle of the journey. They mostly stop at Stockport, Macclesfield and
Stoke-on-Trent (near Manchester), plus Milton Keynes (near London).
Therefore, we also need to consider services between London and
Holyhead, Liverpool and Preston (because they serve some stations
towards the London end of the London-Manchester route) plus services
between Manchester and Bournemouth/Brighton (because they serve some
stations towards the Manchester end of the route). Closer to London,
e.g. from Milton Keynes, there are also useful shorter-distance
We could also consider Wolverhampton, Birmingham and Coventry. These
are accessible from London by the Wolverhampton services and from
Manchester by the Bournemouth/Brighton services.
Taking all of this into account yields the following possibilities
(fastest morning times shown):
to Lon to Man total From
0h18m 2h04m 2h22m Watford Junction
0h38m 1h48m 2h26m Milton Keynes Central
0h48m 2h14m 3h02m Northampton
0h54m 2h01m 2h55m Rugby
1h08m 1h41m 2h49m Nuneaton
1h21m 1h13m 2h34m Tamworth
1h19m 1h58m 3h17m Lichfield Trent Valley
1h25m 1h05m 2h30m Stafford
1h47m 0h47m 2h34m Crewe
1h42m 0h44m 2h26m Stoke-on-Trent
2h02m 0h32m 2h34m Congleton
2h01m 0h23m 2h24m Macclesfield
1h56m 0h13m 2h09m Stockport
1h52m 1h17m 3h09m Wolverhampton
1h21m 1h35m 2h56m Birmingham New Street
1h10m 1h49m 2h59m Birmingham International
1h04m 2h00m 3h04m Coventry
Nuneaton, Tamworth and Stafford come closest to meeting your target of
one hour to London and 90 minutes to Manchester, but none of them
meets the target for both of you. Tamworth and Stafford meet your
original criteria of 90 minutes each.
The shortest total travel times are for stations near either end
(because the fastest express trains stop at those): Stockport,
Macclesfield, Milton Keynes and Watford Junction - but those stations
give one of you a disproportionately long travel time. There's a catch
waiting here though - although you can travel from Milton Keynes to
Manchester in 1h48m, if you travel at the wrong time of day this
journey could take over three hours and involve three changes of
train! That's because only a few of the fast trains to Manchester stop
there. I also found variations in many of the other travel times
according to time of day, but these were usually less than the
variation for Milton Keynes.
Another factor to consider is the cost of travel. Tickets for services
that arrive in London during the morning peak are particularly
expensive. If all else is equal, it will probably be cheaper for the
longer commute to be the one towards Manchester and the shorter
commute towards London.
I hope you find this information useful to help make your decisions.
In addition to the online timetable at thetrainline.com
I also made heavy use of the PDF formats of the Virgin Trains printed
timetables, which can be found here:
These timetables make it possible to see just why there are big
variations in travel time at certain times of the day, and to
understand the "big picture" of the travel time patterns.
Please request clarification if I can be of further assistance.