Use your best judgment about who on the sales floor seems to have legitimate claims to experience and push them for all the advice they can give you. The most important decisions you make will concern your clothing. What you wear in the backcountry is of more than esthetic concern. Winter campers are usually hyper-aware of their core temperature. Far more threatening is a rainy, forty degree afternoon hike.
Wet cotton is more harmful than nothing at all.
Regardless of the weather forecast you must be prepared for dirty weather. The options for foul weather gear are limitless, it seems, but there are a few basic requirements that your rain shell should meet. Do not rely on a poncho, especially the three dollar stadium variety. You need rain gear that will withstand an all-day storm. Staying dry is the first step toward staying warm and safe.