I know what you mean about not having anything useful to work from. I converted my decent sized Denford Mill in 2008 and it's done amazing work.
However, Mach is flaky in my opinion. When you get something that works, don't touch anything. Updrading to the latest build of Mach4 is proving to be a nightmare. Basic things you'd think were set in stone, such as Single Stepping have been messed up. The bizarre thing is that it momentarily worked correctly, and now it's gone back to being wrong.
Anyway, this is what I've done to get it to this imperfect but just usable state...
1) Set up my I/O and configuration from scratch in the new default Mach4Mill profile.
2) Copied the profile to make a new version I can experiment with
3) Installed my screen set
4) Checked to see what works and what doesn't
The results are as follows...
1) Single Stepping is still wrong, it lags behind the actual moves by one step. However, if I go back to the Mach4Mill default profile it works correctly, however there is a definite lag between the digits changing on the DRO and the table moving, and I've not noticed that before.
2) It no longer throws an error report on exiting Mach4
3) It no longer loses the input pin configurations for the limit switches and e-stop
4) Mach4 doesn't seem to crash after showing the Warp V270 splash screen which it's always done.
5) Jogging the A-Axis is almost right now, but not quite. There's still a rounding error in Mach4 that means if you have precisely 1 output step when you click the jog for that amount, it doesn't ouput a step. Instead, it ignores the first step and then outputs two the next time.
In other words, my 4-th axis has 100 Counts per unit and if I jog it using the 0.01 increment, it only increments by 0.02 after I've jogged twice.
Clearly this situation is going to be the same if it's any other axis, so this needs looking into.
I need to make another point about Mach4 that is in direct contradition to everything I've ever read. And that's about dedicating a computer to Mach4. This is utter nonsense, you absolutely DON'T need to do that if you have an ESS. I've been running this way for over 5 years with both Mach3 and Mach4 and have NEVER had an issue.
I stream music, post process huge path files, and browse the internet completely at will. I create complex 3D models and watch YouTube. This is a non issue, despite what you're told. Maybe if you're using a Parallel Port then it's a problem, but as soon as you're using an ESS then it isn't. It's just another process that Windows 10 is perfectly capable of handling. I'm running a 3GHz quad core with 8GB of memory, so it's hardly an amazing computer.
It's massively more convenient to have all of the files you generate on the same PC, with the same screen used for showing Drawings, entertainment and running the machine. I guess nobody tries this because they're scared off by the bad advice.