Yeah, that's true. Only one carpark pass issued now i think. In your case the easiest thing to do would be to arrive at LHR whichever way you choose then catch the Virgin bus to LGW. You can buy another pass for about £40 per month but it's hardly worth it.
For early check in's however you would obviously need to be there the night before. For the few early flights out of LHR (MIA, JFK, IAD) it is possible to catch the 1st flight down but otherwise i normally stay at either the Crown Plaza or the Holiday Inn both of which do a crew rate. Not sure about LGW as we never fly out of there on my fleet but i heard the Ibis is ok.
Yes, it's best to get the train to Watford Junction then catch the Virgin bus to LHR. It's really good actually as they depart about 10 mins after the trains arrive (and every half hour) and stop right opposite the crew room. Plus most importantly it's free for us!
The commute is a big chunk out of the salary and the sby tickets are now £58 as has been mentioned. However the train tickets can be as little as £12 each way which really cuts down the costs. Not sure which part of MAN you're from but if you're near Manchester Picadilly, Stockport or Macclesfield
it's very convenient. The commute costs me far less than the increased mortgage payments i would incur if i decided to move back down south.
Worth it for me but see how you feel after 6 months. You can apply for the MAN base or become an honorary Southerner!
Feel free to pm me if you have anymore questions. If i don't know the answer cos it's LGW or specific cc stuff i'll find out.
Cheers