To play any mod with Alexander features you don't necessarily need to install the Alexander expansion. To get the .exe file, though, you do need it. Once you have such an install, follow this guide.
Playing with Alex.exe guide (original credit for this goes to
Brusilov ):
Now, this is just so you could run the Alex.exe with any mod. But since Rio's mod is meant to be played on BI, there are features that break the Alex.exe upon loading it. This worked for me:
In
descr_sm_factions.txt the following lines need to be deleted (make a backup, of course):
This is just an example. You need to delete those lines for every faction that has the 'hording' ability. An easy way to do so is to search for the word 'horde', that way you'll find a whole section like the one above. Remove everything with
'horde_' in front of it.
That's all it took for me. Maybe there is something else. The shield wall should be broken, but I didn't edit the unit files.. The battles must be tested. Same goes for the other BI features: swimming, night battles.. (I think there is a way to keep the night battles in Alex.) I simply don't know if they work now or do they break the game. But my solution thus far manages to load the game as well as the campaign. Hope I helped, with some feedback I'm sure we'll manage to get every BI mod to run with Alex.. Great for whoever doesn't find hordes, shield wall and swimming an integral part of their RTW experience.
I'm not sure my method is complete, because I did what is expected to not be dumped with an error message trying to load the game. I managed to run it and load my campaign. Some extensive testing is needed to determine if that is enough. Unfortunately I experience nasty crashes and can't help with the testing for now.
If anyone has questions, feel free to ask, I'll be glad to answer if I can.