I had a similar surgery in 2004, a PLIF (posterior lumbar interbody fusion) at the L4-L5, L5-S1 levels. I wore the brace for 4 weeks and then I was free to move about without restrictions, they had me walking 2 days following the surgery, with the brace and a PT with me for 2 days. I had little post surgery pain and was back to normal activities in 6 weeks. I had severe complications not related to the spinal surgery, 1 week after the procedure, so I was a little slow in my recovery.
I have raced motocross worked my job as an engineer on various military construction sites and have ridden steadily since 2010 when I got serious about returning to cycling. I ride between 90 and 120 miles a week with no back pain or limitations on position on the bars (drop) and my stem is normal for a road bike. The surgery made all the difference for me, pain and paralysis were gone and movement came back quickly with range of motion returning to normal in 6 months after being careful and having follow up checks and x-rays periodically.
Best of luck with your surgery, hope all goes as well for you as it did for me.