There is the option of hirail wheels with Kadee couplers and everything else "scale". The are are those who would say it is not scale if everything is not per NMRA. But Brooks Stover has done it effectively with American Models track and high rail wheels Brooks Layout. I think there were a couple others doing that also.
You can still have a scale looking railroad and if you see a must have Lionel AF steam engine it will run. Of course electronics etc has to be dealt with but no need for the difficult wheel replacement. Not to mention if someone sees your new layout and really really wants to run to run his/her vintage American Flyer.
Just an idea and another option.
