When I rewired my boat, I used Pacer Wire, mostly. Ancor featured rather prominently too. Pacer is comparable to Ancor and a little cheaper. Additionally, it is somewhat thicker than Ancor. I found it easy to work and the 2.0 size was as easy to fit around corners as the Ancor brand. I bought mine through Peter Kennedy Yacht Services in Annapolis.
I think Peter sells it in 50' foot links. Yes, I would get rid of the romex wire and those metal boxes too.

Mike Meier