I can completely sympathize with this post. I'm definitely a financially nervous person too, and this trip really helped me deal with it. Almost two years of a steadily decreasing checking account seems terrifying, but was completely worth it for everything I experienced (so much so that I plan to do it again, and hopefully not just once, in the future)
Basically, I just talked to people that had been in various areas to see what they spent on their trips there...and also, compare it to how they travelled...did they stay at Hilton/Super 8/campsites? What kind of food did they eat? Were they going on expensive tours at every destination.
Basically, find what you need to spend on accommodation and food in a given area. After that, what kind of tourist activities do you want to do every day...some are free, some are horrendously expensive. Then, what is transportation from place to place? If you're taking a bus or train, its pretty straightforward, but on a motorcycle, there are more variables - fuel cost in each country, maintenance costs (which can also vary greatly by country).
Once you've figured that out, save up a bit extra for any emergencies that may arise, and you're good to go!