There's a So Cal club of former Cardio surgery folks (SCOR) that'll be more than happy to share their experiences.
I had my double bypass in the fall of '07 (November) so the cycling wasn't an issue.
I got in a lot of outdoor walking (much to the chagrin of the cardio doc and his nurse who swore at me!)
that I guess I wasn't supposed to be doing (I think the mile 2 weeks after getting home was the one that got to the doc and his nurse)
Like you (and several others who've responded) I was active(cycling right up till 3 days before the surgery) and that probably contributed to my recovery immensely.
I'm still on the 12.5mg of lopressor 2x daily.
I 'guess' it has a restrictive issue on my cycling (heart rate) but I can now climb those hills (moderate..I'm far removed from lance armstrong)without the 'heartburn' and the fact I have moderate COPD -which usually brings the HR up anyway-puts the issue of raising my HR to bed anyway.
Two years on and I still get 'stingers' (needle like sensations) in the chest when I sneeze or cough.
Other than that, I don't see any downsides.
Enjoy!
You have a rebuilt 'engine' ))