tis a doddle. Ezy check in in Concorde house, 5 minute stroll from the train station through the terminal. 24 hour discounted Coffee available at Costa by Sth terminal arrivals. I have a 6 zone annual "Gold card" and use it to excess from zone 6 to LGW if i use gat express. Costs £9.10 day return. There is a staff travelcard which gives you a similar discount.
After 9.30 using Southern it costs £3.15 return!
Car parking/bus is a nightmare at gatwick, not to mention wasting/shortening your life sitting on the M25 when you could be relaxing on the way to/from work.
I have a car and usually choose not to use it. I live in W4 and from front door to crew room varies between 1 hour(fastest) and 2 hours(late at night...just missed the 2.15 am london bound...have to wait for another hour..)
Extra benefit if you do overnight flights is that you dont have to fight to stay awake/ alive on the drive home.
W1 should be very easy. I live in W4 and sometimes have to grab a minicab to Victoria for the first gat express at 03.30am.
Just a bit too far to cycle with a flight bag!