If you can, get to a book store and browse the books they have on offer. As you say you have some VB reference books already, can I suggest you look for either a reference to Office VBA or possibly two books, one for excel and one for word, that hold a reference section on the objects and properties. also if you can see the books you can see whether the layout and examples are ok. If you like it, then you can always go online for the (possibly) cheaper book.

If you picked up VB fairly easily, then you shouldn't have a problem with word/excel. The only thing that is annoying is that you need to use a lot of variables for each of the objects, just to get the intellisense working right... mostly.

Go for an intermediate to advanced, so as you get further into thing you can expand and not be wasting money on a book. They usually have the range on the back.

Alternatively, try looking online for tutorials and information, saves you getting the books... Although I prefer some thing meaty to refer to once in a while.