I recently did this myself, traveled for a year and a half through Europe, Australia and Hawaii, while writing software to pay the bills. It was much easier than saving up that much money before hand, and the work was more stable and dependable than trying to find temporary work at each new location. I stuck to countries with good Internet access, where I didn't have to worry about getting mugged or my rig stolen.
Some hostels provide free wifi, but in many cases it's painfully slow, and many hostels charge for wifi, but it can often be by the hour or for really small amounts of data. Basically they're assuming that you're just emailing and facebooking. Many do have a quiet area, but it might not be setup well for plugging in a laptop, and ergonomically sitting there for hours at a time. What worked best for me was to plan on participating with the other hostelers at all the peak times, such as the shared breakfast and possibly shared dinner times, and either afternoon treks or late night partying. Then I worked in all the gaps in-between, usually the late morning, afternoons, and before supper. Staying in the hostel quiet area all that time was very unappealing, so I would use any rooftop patio, or cafe, or pubs that aren't busy and so will allow you to camp out for hours after you've finished your meal, if asked nicely. Libraries are very good, as well as any post secondary schools that might be nearby. When I found a cafe with good wifi, I would return often, and they would usually accommodate me, even asking other patrons to move for me so I could access a plugin!
Since not every place has good cheap/free wifi, it quickly became necessary to get local SIMs for my iPhone, and get data plans that allow for tethering. Luckily in most places outside of North America, getting 1 GB pay as you go is pretty cheap and easy. At times I got 1.5 or 3 GB. It did take some effort to make sure that a wireless provider allowed both tethering and VPN through that tethering, so I could access my company's intranet for SVN etc. Also, having a local SIM will facilitate with communicating with fellow hostelers and locals that you meet. People seem to mostly stick to SMS, WhatsApp, iMessage and Facebook for messaging and coordinating meeting up.
I always kept a very current Time Machine backup of my computer, which I stored separately from my computer bag, which saved the day when my computer did eventually get stolen. Don't rely on a computer that you can't afford to replace. If you can, keep your home insurance up, to cover your possessions abroad, like I did. Also, I use CrashPlan for an offsite backup, in case I lost everything. This helped get back my very most recent work that I hadn't yet backed up to my Time Machine. But beware, your data plan or limited wifi will not readily support regular backing up everything. I added rules to CrashPlan to not backup any temporary or built files, and I would regularly use the feature that allows suspending backing up for several hours, until I was back on a free wifi. Also, don't let your computer automatically download updates. It can take a while for an online backup service to upload everything for the first complete backup, so start that process well before leaving. I used Mozy first, and didn't like how slow it was and the trouble I had restoring files, so I needed to start all over again with CrashPlan. Also, a padded water proof or resistant computer case is a must. Many times I went to a cafe it wasn't raining, but on my return it was. Always lock up your computer in your locker in your room. Not every hostel has lockers in the rooms.
The main thing, is to not shut yourself off from the other backpackers, but to find a balance of socialising, seeing all the sights, relaxing, and also fitting in your work that will pay the bills. This way you will have an even better time than those who are not working but must live within a tight budget as they're burning through their savings.