Glad you enjoyed it. As for the knee pain, a general rule of thumb is that if the pain is in the BACK of the knee you may have the seat too HIGH. If the pain is in the FRONT of the knee,the seat may be too LOW. Pain on the outside of the knee is often IT Band (illium-Tibual band ) issues. Those can usually be averted with a stretching routine. I have to keep on myself to do my IT stretches, otherwise it will rear up and bite me.
As for the rack, every tourer worth his / her oatmeal always has a few zip-ties of various sizes tucked tonto the bag for that eventuality. I also use blue locktite on all the fender / rack bolts, to make sure that they don't come loose. (These lessons learned by trying to fix a broken rack with a piece of wire that I found lying along the road). In a pinch you may be able to use the bolts from your water bottle cages to fix the rack.
Steve W.
If it ain't broke, fix it till it is....