Naw, you're still okay on the Encampment. We were up there last weekend (6/10) and there was still lots of snow up high. Once it heats back up this week it'll have a final spurt. You should go up there this weekend, it's an excellent run!
I've done it at a variety of levels and for what it's worth I would say minimum levels for it to still be fun (not just "runnable") would be 400 at the putin and 800 at the takeout. You can still run it at half those levels, but you'll be HATING life on the last 4 miles of gravel bars, seriously! Even at peak those last 4 miles go on forever.