I got back into model trains when I built my house with a basement and my wife was pregnant. She gave birth to a daughter, and she and her sister who followed do not care a whit about trains except when they run the Arttista figures in the gondola; put pigs, cows, horses, and deer in the woods (and check to make sure there is NO livestock in the catttle cars!); and make trees to plant in the woods.
I run highrail because the priority has always been to run the American Flyer set my mother earned for me for Christmas years ago. (With five kids at the time, she could not afford such an expensive gift for just one of us; so after I went to school, she bundled up two little ones and went out to sell newspaper subscriptions. She won second prize in a contest and traded whatever she won with the third prize winner--for a Santa Fe PA-PB set with freight cars.) That set runs around the track every Christmas in her honor.
Everything else has to run on the American Models track and switches, so the wheels are all high-rail; but couplers are Kadee #808 for everything except the original Flyer set. I run DC for American Models engines with extra detailing, SHS engines, and some of the latest Lionel engines. Only the Challenger requires AC, so I invested in the Legacy system for that engine, a Y-3, and two SD70ACe locomotives for the extra features. It would almost be a scale layout except for the track, turnouts, and wheels because all rolling stock and engines get detailing added to them.