Cranking as it is recharged while you use the motor. Your trolling battery only discharges during use so you don't want to add extra electronics to it shortening your trolling time.
My preference...
Running lights to the engine battery.
Stuff you can operate the boat without to the trolling motor battery.
I've run a trolling motor over 1 hr at full power on the trolling motor battery. If the accessories are significantly affecting that... you probably aren't fishing.
