spinach should do fine from now till when it freezes for more than 24 hrs straight same for lettuces. for me it is not a great idea to plant with out row covers after oct because every thing will go dormant or freeze solid, nothing grows well in snow and ice with out allot of help.
I do have one raised bed with a way to cover it for winter. Don't think I am going to do any thing this winter though need to top dress my beds for spring planting.