For $800 you can get a very good quality used tourer with all the racks, bottle cages, fenders that you need. A 5-10 year old Trek 520 or similar bike in excellent condition with touring accessories can be had for that price and I'd much prefer one to a new Windsor Touring (although it's a fine bike, it's not really in the same league).
Racks are best attached to mounting points specifically built onto forks, seatstays and dropouts of the frame. Not all frames have them. You can get clamp-on or even seatpost mounted racks but I don't recommend these for long trips/heavy loads.
Most tourers are slow. Don't expect much more than 15mph overall unless your really fit and travelling light.
bike to bike comparison
if i just had stock tourer and stock road what would be speed diff?