Let me start by saying I am a complete newbie when it comes to circuit simulation

I have the attached circuit, drawn in EasyEDA.

Is there any free simulation software that would allow me to simulate different scenarios?

From the quick look at simulation software, most seem to handle standard components like resistors etc, but how do I handle the less common components such as the DC-DC convertor and the Heltec Cubecell?

Thanks

 

how do I handle the less common components such as the DC-DC convertor and the Heltec Cubecell?

You need a simulation model for those from the manufacturer
Unfortunately those are often not readily available.

 

From the quick look at simulation software, most seem to handle standard components like resistors etc, but how do I handle the less common components such as the DC-DC convertor and the Heltec Cubecell?

It would be unusual for simulation software to be able to deal with microcontrollers or single board computers. Personally, I think simulating voltage regulators with anything more than the simulator between your ears to be unnecessary.

 

Personally, I think simulating voltage regulators with anything more than the simulator between your ears to be unnecessary.

So you don't care about the regulator's current-limit, minimum voltage drop, or regulation characteristics?