Figuring it out by ear will really be worth it, just take your time and understand that there may be sections you won't be able to get exact.
1. Make sure you know the key of the tune and the chords being used. This will give a rough idea about what notes might be used in the solo.
2. Listen to the solo and try to SING ALONG. Try to get the rhythm as well as the pitches as best you can.
3. Once you can sing a few bars, go to the bass and try to find the pitches you're singing. WRITE THEM DOWN as you do this!
4. Once you have a bar or two done, go on to the next.
The more often you do this, the more you ear will improve. I can guarantee you that you will learn a LOT if you spend a few weeks (or months!) trying to break down this solo.