In the Undertale folder you will see a file called "data.win", if you don't see it, then scroll down. Make a copy of the "data.win" file somewhere else on your computer, then change the name of that file to "game.droid" the right-click on it then "Cut". Okay, now take a ...
for this. Then, change the font mid-line in whatever program your using and then either copy the character from the Character Map or hold down the “Alt” key and type in the numbers. The character should appear. Again, sometimes they don’t if your chosen font set lacks the characters...
Some games save locations wont change at all as it depends on who cracked it, and how that crack/emu is setup. So, without playing this myself and seeing it with my own eyes. I would have to say (copy/paste) your old save into the new saves location. as for "locations" that is...