It's going to be huge this year, the question is when. The long-term forecast is for wetter and hotter than average. xxx buddy. If it were me, I'd target late June. It's likely to be huge then. Some big years peak in early July, but on some big years peak has come and gone by then. I recall something about the mid '80's where it got warm and wet (rain) in early spring which burned the snowpack, but resulted in temporarily silly-high boating.
Here's some tools:
Geek out on historical big snow years. From what I recall, 2008, 2011 and 2015 were some of the biggest recently. Peak flows generally occur just as SWE drops to zero.
Climate predictions. These are more right than my best guess, but I am not a NOAA scientist.
Web CDSS Streamflow
Historical flows. This site is a bitch to navigate, but if you know the gage you want, you can pull up nice daily cfs summaries.
If this year ends up being as good as it looks, much of the Crested Butte stuff will be snowed in or stupid high in late June. However, that means that the Ark will be at a super fun high level, Clear Creek of the Ark will be huge, Clear Creek of the front range will have boaters passing cars on I-70, Boulder Creek and all the Poudre stuff will be absurdly high/fun. Castle Creek and Slaugherhouse of the Roaring Fork will be in the high-fun-zone. Did I say the Ark? Because, although I'm a lame boater, I can't think of anything more fun than 3k+ on Numbers and 6k+ in Browns.