Check out this article in today's Everett Herald.
It tells how, where, and when boondoggin' was invented.

Cigar
http://www.heraldnet.com/Stories/03/10/2/17563118.cfm

Quote from the article in the Herald:
"Before most of you were born," Yama$hita says, "logging outfits transported logs down the river in tied-together 'booms,' to market. The men who tended the booms often fished by bouncing their bait downstream while sitting or standing on the logs. Because they weren't working very hard, they were accused of 'doggin' it,' and eventually that form of recreation became known as 'boom doggin.'"

That is close to what I have heard around the Skagit with the exception that the early steelhead anglers discovered that the passing log booms stirred up the fish and caused a 'bite' as they moved down the river and so they followed or 'dogged' the booms to stay with the 'bite'.

With the advent of moter boats the Skagit fishermen discovered that by motoring through a hole once or twice before fishing it that they, like the booms, stirred up the fish and often initiated a 'bite'.

The practice of making more than one drift through a hole became one of the standard approaches to fishing here and became known as boondogging.

Although it is no longer necessary to repeatedly fish a hole, most any practice of drifting through them while fishing is now broadly covered by the term.