As long as your track is hitched down securely, I see no reason why it shouldn't work with the little ones just fine. My grandchildren, a little older ran my 4x6 when I got it wired up, seemed to enjoy it for a little while. Didn't have it wired for more than one train runnintg at once, but they could change the route. Did use a power pack that could be set so the trains didn't fly off the table, as grandson was looking for SPEED!
Some simple scenery that would hold up to little hands and storage will improve the looks and fun. A few buildings will add to the looks also. They may not be ready for operations, switching and changing cars, so have it so they can change routes easily, even if it is just parallel tracks.
Have some things that are durable, even if not in scale, for them to play with while the trains are running. Also, use a simple engine and cars that perform well, but don't have easily brakeable parts.
A little paint and scenic material will make a world of difference on the layout and be fairly durable, without too much cost.
Have fun,
I am currently thinking about a small HO 4x6 christmas layout for next year on a plywwod board and was thinking about using some of the Bachman ez track that came with Thomas the train.
Due to space it will only be up a few weeks and then put away till the following christmas , trains will mainly be operated with my three granddaughters age 2-4-6 with adult supervision.
any ideas if this would be kid durable
Rich