I've been making the trip to LFP about twice per year. I am appr. 2.5 hours away (from west), but if traffic or other conditions aren't favorable, it can be longer. I am traveling from the west and I usually take Hwy. 380 and jump on DNT (Dallas North Tollway). I've tried the trip Hwy. 380 to 35 S, to 35 E S, to George Bush Tollway yada yada. I found that it was MUCH easier with fewer contingencies to simply remain on Hwy. 380 exclusively and hit the DNT. DNT seems a bit busier than it used to be, but still a (relative) dream.
There IS a fair amount of stop and start (lights) on 380 (traveling east) past Denton, yet the traffic always seems to keep moving rapidly and ultimately is the shorter trip.
I have gotten into the habit of searching TxDot website before leaving home. Enter TxDot into search engine. The site includes specific info on construction taking place and other known delays. Not such a big issue if you have plenty of time, but if your appointment is same day, this can really help in planning time allowance.
O/t a bit, but the people in Plano and surrounding area are generally VERY congenial, at least to this out-of-towner's taste.
Happy travels everyone.