Am I half way through writing my book or is it nearly finished?

My travelogue memoir is now up to 34000 words.  I have been reading and re-reading it, over and over again. It's good, informative, entertaining and also very amusing.  You see I can't write 'serious' for very long.  I could never write a serious 'how to' book.  'How not to' - no problem!  I'm one of those writer's who find life very amusing and I have a zany approach to life. What do you think dear readers?  I know I have two (three if I include myself) regular readers.  Are books far too 'serious'?  Should we be laughing our way along life's conveyor belt?  How many words do you think there should be in a travelogue?  When is a book finished?  Is it time for me to write another zany book?

Answers on a postcard or maybe a comment or two.  Ta very much.  And to quote that Monty Python song:

"Always look on the bright side of life.."

Did I see you whistling then?