If you do decide to fly, keep a close eye on oil consumption and consider an early oil change (after 5 hours or so) plus oil analysis. At the same time you might want to do compression testing of the cylinders.
And what about your personal currency? Are you current enough to deal with EFATO and other things the aircraft might throw at you? Maybe it's a good idea to do an intensive workout, practicing things like that, in an aircraft that has the same flying characteristics of the ATL, but hasn't been grounded for a year.
Oh, and a minor thing: It might be a good idea to flush out all the "old" avgas, replace with new (or at the very least a mix of old and new) and run the engine on the ground at high power for a few minutes. As I understand the aging characteristics of avgas are quite good (better than mogas) but you still might suffer from gelling or deposits in the carbs, fuel lines and tanks after this long. Also check all drains, fuel selectors and fuel cutoffs to see if they're not seized up.
You also might want to recharge the battery on the bench using a suitable charger, rather than do that while the aircraft is flying. And check tire pressure and so forth.