One route you could consider, and one for which my helicopter course is aimed at - if you get an ICAO ATPL and 1000 hours, you don't need to prove any training as you will be exempt (just tick the box on the exam application form). You will also need 500 hours on a suitable type to avoid the TRTO course as well, but a Canadian or US ATP would be easier to get short term (which does not mean that they are a pushover - although the writtens might seem "easier", the practical flight test can last most of the day).
Of course, family commitments, etc may well blow this out of the water but if you're in a mood to run away and join the circus it could work.
Otherwise, the ATP is the most cost-effective, but you have time pressure afterwards. Expect the whole process to take at least 6 months, including the exams, studying Mon-Fri, 9-5.
Phil