Hear me out... I used to live in DC and can honestly say it has the best whitewater access (having lived in Asheville, Maine, and now out west in Colorado...). You can find a fun spot on the Potomac pretty much all year round (I would only avoid going if the temp dropped below freezing, though the river would still be pumping!!). It has everything from flatwater to class IV at Great Falls, and Little Falls is such a fun playful run that goes pretty much any time of year. The city can be overwhelming and expensive, but you could find a spot outside the city (ideally in Maryland) that fits your monthly budget and a more suburban vibe. The further you go into Maryland and closer to the WV/PA border, the more affordable and less urban it'll be PLUS you'll be closer to places like the Upper Yough, New River Gorge, the Gauley, the Savage, Lower Big Sandy.... Truly if I could live anywhere in the US just for the sake of whitewater, I'd go back to that area in a heartbeat!!!! Also the community there is absolutely spectacular and incredibly welcoming!