That's good, because N-gauge
is small!
There's z-scale if you really want to push it!
I have a 2' x 4' N-Gauge set up that I haven't done anything with in decades. Just too busy in retirement!
Maybe this is the year that I get it checked out and updated, as the oldest grand-kid will be 3 (maybe a bad idea, he'll want to grab it!).
Last year I spent quite a bit of time tweaking the Lionel Tin Plate I inherited from my FIL, a ~ 1936 model. I've set it up at Christmas for the past 10 years or so. Found some replacement parts on line to fix the broken/missing parts, and I updated a Signal Bridge and crossing gate from our old family Lionel layout. I converted them to work on DC from the transformer AC, Signal bridge to red/green LEDs that are switched from an insulated section of track (the train wheels make the contact across the two outer tracks), and with some large filter caps and auto brake light bulbs as current limiters, I got the crossing gate to run smooth as silk (on AC it would buzz like a bee!). Cleaned the motor, lubed everything, and got it running smooth (it used to be hard to get it to run w/o a hand on the throttle, it would either speed up too much and derail, or stall out).
The grand-kids enjoyed that train last year, but couldn't understand why it wasn't there in late January! The youngest one wasn't talking much at the time, he would just drag me into the living room, and point to where the train was, with a quizzical look on his face. Train?
I'd say just go for it. Look for the better quality locomotives, I forget prices, but going up from the lowest price generic stuff to the more mid-range stuff will be a big improvement in how smooth they run, and I don't think we are talking big bucks. Of course, with any hobby, the sky's the limit, but you don't need to spend $1,000's for a good N-Gauge loco.
-ERD50