With high water coming early, I just checked with the Blairmore Forestry service about the opening of South Drywood. Apparently, it won't be open until the 15th of June and closes at the start of September. By then, I am sure the high water will have gone. Alternatively to access the valley one can get a research permit which gives you a key to the valley. You need to contact the Blairmore forestry service with a letter of request. It should be on department letter head.
Perhaps I will need to make a trolley to carry boats up. There are quite a few people keen on doing it. The may long weekend event would be perfect.