Do a compression check.
A piece of Cast Iron has no intelligence, It can't tell if it's at idol or at 2,000 rpms. The worst thing about not ever driving your car is not the engine, It's the rest of the car, Rear end gears and bearings, trans gears and bearings, shocks, leaf spring ends, ball joints, front bearings, steering box, U-joints and the list goes on, all have to be exercised, or they corrode.

 

If it were mine I'd be doing a leak down test and a cooling system pressure test.

You're right, cast iron doesn't know how fast its running. As far as the rest of the items you mention, a "properly" stored car will not have any of those issues. However all the condensation from cool oil will continue to build up and get worse, even if your water temp is up the oil temp is not. Then you have all the carbon buildup which will continue to get worse.

In the end it's your car and your choice. Keep idling it and we can keep having threads about milky oil and carbon build-up on valve seats.

 

Good points, I'll never understand why oil temp gauges are not part of most cars. Not only do you need to get the oil temp up you need to keep it up to evaporate all the condensate and get out of the sump.

Cold motors have lots of blow-by, one of the byproducts of combustion is water (very acidic in combustion) which ends up in the crankcase. It just makes the condensation issue that much worse.

Where do you measure your oil temps? On two of my motors under heavy load, in order to keep the oil from going over 235 in the pan I need to run huge oil coolers that knock the oil temp back down to 150 before sending it back through the block.

 

Start it up cold with the radiator cap off, if you get major bubbling/puking out of the radiator neck before the thermostat opens, you have a blown head gasket or cracked head.

The absence of bubbling or puking won't prove that you don't have a sealing issue, but it is a good indication that you might not.