Thanks, all! The consensus confirms what I expected - Senior 4 would be easier than Master's 55+/60+ Open, or Master's 40+ 1-4. I know how badly I was spanked at the one Master's race I did. Even so, I'd like to race with guys my own age. I've got lots of time to decide, but I'm leaning toward a version of caloso's suggestion - sign up for a stage race as a 4, and race the Master's crit too, assuming it's within the rules. As for working toward Cat 3...that's not a goal at this time.

If I can get some results as a 4, that'd be great. If I'm destined for pack fodder either way, I'll just ride with the other codgers.