Potential Global Warming Crisis on My Layout???

Well definitely keep the boxes away. IF you are worried, I would place a deflector shield between the table and the Radiator or a Fan to disburse the concentration of heat.

Suggestion:
You could put a piece of metal sheet between with a 1" or so gap between the bottom of the layout and the radiator Do not lay the metal directly on the radiator. Then hang a small fan on the underside of the layout pushing the air from one side of the radiator and out.
This way the hot air would not be trapped under the layout and the metal will help stop the direct heat from hitting the bottom of your layout.
The other easier option would be to shut the radiator off

well, it isn't a good location - the convection from the floor to the ceiling is what distributes most of the heat.

I have a table that goes around a taller one. When I covered half of the top with a half-mountain shell it severely affected the warmth of the room. I attempted to wire tie a 120mm high cfm computer fan to the end and it didn't move enough heat.

Perhaps a 9" or 10" type of small fan on the floor would work better.

I removed the mountain and I am contemplating how to disguise it.  No fans needed now and warmth is fine in winter again.

If the larger fan worked out and you are comfortable with 120vac wiring, you could possibly automate the fan with a line voltage type thermostat. It would take a little bit of line voltage wiring/rewiring though. A remote bulb thermostat would allow you to sense the temperature below the table and mount the thermostat somewhere more accessible for easier adjustment. This type of thermostat might be a bit pricey though? I'm guessing at least $50-$60 or maybe more?

Here's one that looks like it would work. Less than $50, but not by much. You would want 'make on rise' to turn on the fan when it gets hot. This one does both and also has high amperage rating, should be more than enough for a circulating fan.

This one may be a better deal. It's 'make on rise', high amperage rating and just over $50, but they offer shipping on any order over $50.