We originally had a rather ambitious travel plan that involved stops in Kalaw and Inle (a small mountain village and large, picturesque lake) but after a recent plane crash with our preferred airline (out of Myanmar's several dubious domestic airlines) I decided I just couldn't cope with the stress of internal flights. It would take serious anti-anxiety medication just to get me on the plane - not how I want to spend my 30th birthday.

Stories of the bus route are the stuff of travel legend. Imagine a 30 year-old mini-bus with plastic chairs stuffed down the main aisle to make room for more passengers, slowly winding it's way through curvy roads with multiple people vomiting from travel sickness (myself likely to be one of them) at any one time. Can't do it, just can't.
It is (predictably) illegal for foreigners to hire cars or motorbikes in Myanmar.
With not enough time to travel by ferry, the words of Paul Theroux's 1972 travel memoir The Great Railway Bazaar in which he journeys from the UK to Japan by train came to mind:

In The Great Railway Bazaar, Mr Theroux takes a phenomenal journey through then Burma all the way north to Lashio (sadly, we won't make it that far). A part of me is hoping that Burmese rail travel hasn't improved much since 1972 (a hunch tell me it probably hasn't) and am hoping to experience all the same frustration, delight and faded colonial grandeur that Mr. Theroux encountered.
Our journey will be but a miniature version, 17 hours overnight straight north from Rangoon to Bagan. I've got George Orwell's Burmese Days on my Kindle (a battered paperback would be more 1972, but whatever) I'm looking forward to it.