From what I can see they released a 25th anniversary version a year or so back (that is to say still actively sold) and it is not open source/leaked source. Everything makes special note it is very different to oregon trail (probably also the organ trail but different discussion there) so you don't even have the limited remake options of that one ( https://github.com/TheRedSpy15/The-Trail ) really.
1995 era PC (and mac) means without looking I am not sure what languages it will use -- that was right on the jump from assembly to C for games, with this being simple enough as a game that they might have gone either way as there are benefits to both, and even if it is C I would still expect a weird compiler and libraries, as well as a whole bunch of inline assembly. It says it supports Windows 3.11 so you might want to look into what any 3ds ports of dosbox can do but I don't know what goes for that one.