"Do you have any Suggestions for speeding up this process. I am happy to buy a high-speed external drive don't know which one would be fastest. Should I be looking for USB or FireWire? is there something specific I should be looking forward to determine the highest speed?"
My strongest suggestion would be to NOT rely on "cloud" backups.
Instead, create and maintain your own "hold-in-your-hand" backup.
Backing up 100gb of data is easy if you have the right equipment, and won't cost you much at all.
You shuttle back and forth between several locations, is that correct?
Do you take your computer along (i.e., laptop), or do you work with a _different_ computer at each location?
Probably the easiest way to stay backed up is to buy (or build, which I prefer) your own external backup drive, and carry it with you. I would suggest something small and portable. A good external case (no financial interest):
http://oyendigital.com/hard-drives/store/U32-M.html
Then just use the 2.5" internal drive of your choice.
A small screwdriver is all you need to put it together. DO NOT BE INTIMIDATED BY THIS (shouting is intentional). If I could do it, you can, too.
I would HIGHLY recommend using either CarbonCopyCloner or SuperDuper to create a bootable clone of your internal drive. This gives you an exact, bootable copy of your computer's drive. If something happened to the computer enroute, with the backup "in your pocket", all you need is another Mac to keep going. INSTANT bootability and access.
I would also recommend keeping at least one additional backup at the location you are at the most -- or, at the one where you have a "secure place" to store a drive.
For doing this, I like "USB/SATA docking stations", which can be bought for under $30, and use "bare drives" (can be either 2.5" or 3.5", the dock accepts either). To see what I'm referring to, go to amazon.com and enter "usb3 sata dock" in the search string.
A USB/SATA dock can be a VERY handy piece of hardware to have around, particularly if you need to juggle several drives.
Again -- I WOULD NOT rely on "the cloud" in your position, especially if you have data that is important for work that you might need to access quickly.