We replaced our bedroom slide topper. Ordered the material from PPL and I followed Carefree of Colorado's website instructions step by step. Follow your manufacturer's instructions on the lock out of the recoil springs carefully, as jesilvas mentioned. The hardest part was being careful not to damage the new cover, feeding it into it's track while working from two step ladders...two persons definitely make it a much easier install.
The mirrors, I can't comment. Luckily, our RV came with 'em.
Jan and Bob