I see no reason why running multiple scripted AI objects should have such an impact, even on a 10-year old computer - if anything, the complexity of the 3D models/textures will have an impact, but not the control logic updating those scripted AI objects at 1-2 hz
As a matter of fact, you can try this for yourself by running the tanker - which is using the same mechanism (AI objects controlled from scripting space). I doubt that you will see memory utilization/frame rate grow significantly. I believe ThomasS created an add-on called "ground services" that is using the same approach to control a handful of vehicles, while those are obviously not moving at 300 kts, this could still be used as a stress-test to see if your system can handle scripted AI objects - but again, I see no reason why this should have much of an impact at all, even on a 10-year old computer.
Tutorials are commonly added to aircraft, i.e. since you will have to load an aircraft anyway, you can simply pick your favorite aircraft (even the ufo or ogel) and add your tutorial to it.
For an example, refer to the c172p which has many tutorials already.
But you can also use a custom PropertyList XML file and load the tutorial stufff via --config.
If you are just starting out, I would suggest to take an existing tutorial (a really simple one) and copy the whole file load that separately. You can then unnecessary remove stuff, so that you end up with a really simple boilerplate piece of XML code.
http://wiki.flightgear.org/PropertyList_XML_File
http://wiki.flightgear.org/Tutorials#Using_tutorials
To learn more about using --config=mytutorial.xml, see: http://wiki.flightgear.org/Command_line_options