To wander back to a point halfway through, I would always opt for the original - but also remember that the best kept secret of editing is punctuation. You should be able to keep all of those words with all the wonderful and uniquely personal nature of your dad's voice by picking your pauses and punctuating accordingly. Don't be afraid to break things up into sentences, even if they're Molly Bloom-style streams of thought. One of the things about any transcribed dialect is that it takes very little time for the reader's 'ear' to adapt and for what you might call 'the voice in the head' to learn to speak. I remember the first time I came across broad Norfolk dialect and it seemed as incomprehensible as Sanskrit, but after a few pages, blarst it bor, Oi hed it in mi hid. And good luck with the project; I just wish I had listened more (and recorded anything) before it was too late.