Bank Shot by Donald E. Westlake

With the help of an unusual set of cronies, bank robber John Dortmunder puts a set of wheels under a trailer that just happens to be the temporary site of the Capitalists' & Immigrants' Trust and hauls it away. But when the safe won't open and the cops get close, Dortmunder realizes he's got to find a place to ditch the "bank."

How to steal a bank
step one: wheels, then... you know what?
Don't even bother.

I read this book around 1988. What I recall is laughing so hard and for so long that my sides ached. Westlake is a literary comic genius on a par with the late Douglas Adams, but in a different genre. Given, I am more selective regarding content now, and recall that some content was a bit “colorful” ;)
I cannot recall the content very clearly, but this would have to be the funniest caper I've ever read, hands down. Maybe I'll bite the bullet one day and read the thing again. Maybe the minor demerits will not tarnish the massive collection of guffaws and cleverness :) Thanks also to the New York Public Library system for loaning me a lot of great books including this one.