I went there in Aug 2015 midweek and didn't see anybody or hear anything. I only made it as far as the northern site after battling a brutal headwind on the river to get there. Part of a trip starting at Rock Lake through the low maintenance route to Little Cauliflower then to the South Mad river. I really enjoyed the scenery on the return along the river so I think it's worthwhile to give it a shot.

Here's more info but probably not helpful and quite dated but..

I visited Madawaska Lake in July 2011. Stayed at the north site for the first night, then switched up to one of the southern sites for the next two nights. All sites are what you would expect for a low maintenance route. The north side had a rock you could at least swim off, I don't recall much of the south site.

Now, despite it being July - we saw no people and heard no motorboats. We debated checking out the cottage but decided not to.

It's a nice lake but Cauliflower Creek sucks (at least it did back in 2011) and my trip through the area is the reason Jeff's map notes that taking the road, though long, is easier then the creek. We took the creek in and the road out - completely bypassing all of Cauliflower Creek on the way out. We took out at the south Madawaska River (P1440) then followed logging road to connect back to Hay Lake where the logging road crosses P985. Longest portage I've ever done.