Hi Christi,
Thanks so much for your question.
Disney's Port Orleans Resort - Riverside is a beautiful Resort with a lot of land and several bus stops. I think more often than not, waiting at the main bus stop, located outside the Colonel’s Cotton Mill building, will be your best bet.
However, bus routes are subject to change due to high or low demand so there is no way to say which stop will load or unload first. Many times, there will be a Cast Member at the bus stop making sure everyone gets to where they want to go or request another bus if needed. If the main bus stop is quite a distance from your room, you could very likely spend as much time walking there as you would waiting at a closer bus stop, so you'll want to take that into consideration as well.
The last time my family stayed at this Resort hotel, I found a lot of helpful information on the unofficial fan website, portorleans.org. It really helped me get a lay of the land and plan our days.
I hope you enjoy your wonderful vacation! Say hi to
YeeHa Bob for me!
Andrea U.