I like the idea of lying above the morning mist, although no IMC or IR would limit me a bit!
Actually a layer of morning mist might be one of the trickiest conditions to fly in, if you don't have an IMC or IR.
The mist might look doable from ground level because you can see blue-ish sky and a watery sun above. So you take off and find that the only thing you can see is mist, with virtually no ground features (apart from the occasional high mast or other high feature) visible.
Furthermore, as the sun comes up and starts heating up the ground, that mist layer may rise a bit and become an OVC002 layer for half an hour or so, later becoming BKN005, then SCT010, then FEW020. But do you have the patience and fuel to wait that out?