how many areas are close enough to you to be attractive for the period of time you ahve limited availablility? Maybe another area might just have a relaxed enough attendance policy to accomodate??
Here is another thought, If, and I donl;t know your situation, you do NOT need passes for family or any other accomodation from the hill/patrol, why is a comittment even necessary?, do what you can when you can. This assumes also, that your patrol doesn't have a waiting list of folks to take your roster spot.
I did the "secondary" registration route this year with a small, relaxed hill where my girllfriend teaches. I go saturdays while she teaches and will probably fulfill more than the hill requires in hours this season. Their required hours and schedule are significantly different and more lenient than my regular hill. They have a core of ops folks that are alos NSP so the volunteers have very little commitment.
As to the "crash course" thang....we have at least one patroller a year lately that misses all teh refreshers in the region for one reason or another. We hold a one evening event that is vetted by the Region/division OEC guru. When you have a 1 to 4 class size you really can run a refresher course in a couple hours.