From what I've seen...
...merchandise host/hostesses are likely to work both outdoor and indoor locations over the course of a program. If you're at DAK, most locations are outdoors; in the other parks it's more like 75/25 indoor vs outdoor. Once you've completed training, you'll probably experience a variety of locations.
You'll have a lot of guest contact. As a WDWCP member working in the parks, your shift is likely to begin midday or early afternoon and extend late into the evening. Up to about 3:00 the pace is generally a bit slower and you can have some great 'magic moments' and 'take 5's' with guests... After that, there isn't so much chatting as people are generally in a kind of transition... deciding how much energy they have and what they want to do for dinner and the evening. Some of the younger set may be getting tired and need a little cheering up.
As the parks close, merchandise locations are so busy, lines form and guests are likely to be focused on reaching the front of that line, making a quick purchase, and heading on out. So you learn to 'ring' fast.
Then all the busyness passes, and the last few guests depart your location as you do your final restocking and count your cash drawer or apron. About then, you'll hear about a party here, or a group going there... You'll find yourself doing what your guests were doing back at 3:00... deciding how much energy you have left for the evening.