MN riders do Nemadji and St Croix meet?

Quick question for MN ,riders can you access the St Croix trail system from Nemadji trail system or vise versa? Is the Northern St Croix difficult?
I remember last year getting stuck in the Northern part of the St Croix, there was a lot of water and I was by myself. I was lucky to get out, I went a couple more miles more North and then turned around, I did not want to push my luck so I never found out if they meet.
Thx for any information.