It's actually quite fun. You can do the fun bits, then degenerate into the least fun parts and spice them up to fit with what you wrote for later. This is what I'm doing right now to catch up with the NaNoWriMo running word count. I need to get back to speed, so I'm going into the most interesting chapter to beef it up until that point.
Well, back to writing.
Wish me Luck.