Mixte has a 14-28, should I go to 13-32. 14-34, or 14-38 to make hills easier?

[SadieKate]

This is a very complicated question to answer without knowing anything about your components or your budget.

First - you need to research the chain tooth capacity of your rear derailleur. Since you are talking about 5-6 speed freewheel, I'd guess you have friction shifting but this also means researching your derailleur maybe a little tricky.

Second - you need to determine if your front derailleur and shifters will handle a triple crankset. With friction shifting, you might have the option of a triple crank which would give you better options for dealing with a trailer, weight and hills.

Only then will you know what options you can go with the components and cost.