Crit racing can be a lot of fun and is certainly less of an ordeal than a triathlon. If you have a local series, you can race as often or as infrequently as you'd like and get something out of it. It's supposed to be fun.
In regards to training, unless you are of exceptional talent I would expect to spend around 8-10 hours of cycling/week to be reasonably competitive.
Lastly, we do have a Road Bike Racing sub-forum where you'll get more useful, informed and experienced advice than you will in Road Cycling. If you'd like me to move it, just reply here or PM me. Happy crit racing!
Cheers,
Tmonk, forum moderator and racer
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"Your beauty is an aeroplane;
so high, my heart cannot bear the strain." -A.C. Jobim, Triste