Dear me,

Wow, you have your pick if anywhere in the country!

Marc Adams, College of the Redwoods, American Sycamore are the
more formal schools that might have short programs.

Then there are individuals - Dave Marks, Patrick Warner are two
that I know have instructional classes or one/on/ones. There are
others.

You need to figure out your needs - what new thing do you
want to learn (dovetail joinery, french polishing, chair making,
etc.)?
Figure on your budget (including hotel room, meals, air/car fare).
Then you can do a search.

Take whatever suggestions you get and balance them out with your
parameters of what I suggested and get going!

For me, there's nothing better than one/on/one or a specific class
on a tool (table saw, router, etc).

Good luck!

MJ