Well.. does he do well in carriers?
I guess there's a lot of stuff you need to weigh, besides cost for airfare. Like... when you stay "stops" do you mean layovers, or switching planes? If your trip requires you to switch planes at all, I wouldn't take him. What if they lost him? It happens a lot more than you hear.
He won't be able to have water on this trip, so hopefully he likes canned food. I don't think I'd be okay with a cat without water for almost a whole day, with only dry food to eat. And a litter box.. he will need to relieve himself on the trip, that's for sure. You'll probably need to build a custom carrier for him (to fit a small litter box and bed, and hand a food dish off the side somehow).
So that versus leaving him there. Option 1) boarding. Can be pricey, but if you get a good place you know he'd get the care he needs and attention/etc. He may or may not be the same cat when you come back though.. I mean, nothing major would change.. but he will be older. You'd be guarenteed to get him back on your return. Option 2) Having a friend watch him. Do you have someone you'd trust with his life? They'd be in charge ofmaking sure he gets what he needs and whatnot... what if they fell in love with him in the 2mths and didn't want to return him? It has happened. A contract would be a necessity here and friends might be offended by that. What if they lost him outside by accident?
It's a hard choice. I'd likely board him. More money, but he's be safest and likely you'd sleep better knowing where he was (and having access to the good vet care). If it was a couple years, I'd bring him with me.. but for 8 weeks? It's not worth the stress on the cat to me.