The worst part about the 777 is the schedule. It is very inflexible. When you get your bid, you have your bid. Very rarely can you swap it with another trip. And the trips are long. Need that special day off for your sweetheart or kids? Sorry. And that's assuming you'll get trips, which isn't going to happen as a new hire.
And it takes 4-7 days after you get home to get back on a normal circadian rhythm. Same for when you go to work.
I bid off the 777 after four years in the right seat, when I noticed that I was getting 48-hour layovers in Paris, and I wouldn't leave the room (other than to eat once a day). I'd rather eat a cliff bar and go back to sleep.....
Call in sick and you blow 90% of your sick bank for the year. And no chance of earning it back.
And even though I lived in a 757 outstation I couldn't jumpseat to work, due to the duty day lengths. Legally I could, but I didn't want to answer for it if something bad happened.
Right as I bid off it (2014) the 777 started getting some domestic flying (I flew 2 domestic legs in 4 years). If you could break it up with a month of domestic every now and again you might could have a better lifestyle.
By the way, on the 777 I was sick all the time. At least one ear infection a year. After moving to the 767 I haven't had so much as a cold in a year and a half.