If you leave them with an autofeeder set it to feed 1/4 to 1/2 the normal amount. When I was gone for 3 weeks this summer the fish were only fed every other day & only once instead of the usual twice. Lost 1 rasbora, MIA, out of 8 tanks.
Less lighting helps too but a little algae or biofilm can help fish survive. No major plant trimming before you leave either. It may be overgrown when you get back but I think it's safer.
I know you have a pretty long trip in cold weather, taking the fish with you sounds more risky than leaving them IMO