There are two options for travelling computing. Either mobile network access or offline data and opportunistic sync. Neither covers every case. The advantage of mobile network access is that everything you need is as fresh and up to date as possible. The obvious downside is that the network is not available everywhere and compared to what you've got locally it's very slow. Besides that, sometimes you have to work with files that are enormous and just too big to transfer remotely.
The other option is synchronisation, but it obviously has its own problems. You need to know in advance which files you need so you can download them while you have access, and if you're not the only one working on them, you might need to merge your changes with someone else's when your copies synchronise again. The advantages are that anything you have downloaded will be available immediately, regardless of how unreliable or unavailable the network is, and the synchronisation can just work in the background without bothering you.
Is there a way to get the best of both worlds? Either one of those can get closer to ideal, but I don't know what the final answer should be.
Mokalus of Borg
PS - My preference is offline data with sync.
PPS - Possibly just because I've found mobile networks so unreliable.