That's a great deal.  I can't imagine why you'd let anything stop you if you have any large scale interest in anything.  FWIW I have a set that's 25 or 30 years old, and we only use that track around the christmas tree.  It's still just fine.  It had the "good" drivetrain but plastic valve gear, whatever iteration of Tweetsie that was.  It's a runner.

I am a huge fan of the 2-4-4-2 look, and as much as I love the little river Mallets, they were standard guage.  So I think I would have to be happy building my own.

They may be true of Disneyland, but Disneyworld has real 1:1 scale narrow gauge Baldwin Locomotives.  3 of 'em.

I am sooooo happy!   Consider me converted to On30.