How would I store large numbers of values (For RPG)?

I have plans to make an RPG that is similar to those on the SNES as far as movement goes- you walk one tile in a direction at a time and if the tile that you are trying to move to has been marked as one that can’t be walked on, it stops the character from going there. That means that conventional collision wouldn’t quite cut it.

So I decided that I would make it to where every tile will have a specific value (one to say that there is no collision, another to say there is, etc.), and every object will have an X and Y value that changes in relation to the character (because there is scrolling in this project).

The thing is, there will be a lot of objects, and there will be a lot of tiles; this will quickly become an unimaginably huge project if I just go ahead and throw objects in.

So, what would be the most efficient way of storing these values? I was thinking of storing it in an XML file or a class, but I haven’t really done it before, so I want to get a second opinion before I try and do so.