The Wikipedia page for Knots is actually very helpful for the crossover episodes sync, and has a full section devoted to where they connect. That should be all you really need. But I also cross-checked airdates on occasion, and the now sadly defunct Knots Blogging site's recaps (still available through cache or the Wayback Machine) which interconnected them.
I am only fully watching KL Season 7 and Dallas Season 9 (the Dream Season) in sync though, due to the creative swap with the showrunners. Otherwise I have largely skimmed and dipped in and out of small or large chunks of the run of Dallas over time because frankly, it's often boring and repetitious.