There have been some articles and a "series replay" in Operations, the MMP/Gamers magazine. But they are not available on-line.
I wound up buying Operations 45 and 47 on an auction site. 45 is excellent - it has a good primer for each section with tactical suggestions for both sides, as well as options to make slight optional rule tweaks for play balance. It also lists about 15-20 optional rules, many of which provide historical 'chrome'.
Ops 47 is pretty good as well, it mainly lists (IIRC) how to set the game up to simulate Operation Comet, which was an theoretical early September variant featuring (again, IIRC) only the UK 1st Airborne plus the Polish Abn brigade, and fewer German and XXX Corps troops, with the objective still being Arnhem. The idea being that the mission may have been possible, even with fewer Allied troops, if the early date of the Op allowed for the Highway 69 corridor to have a lower German troop density, probably similar to what they thought they would face for the actual Market-Garden Op.