Runes of Virtue is a console-exclusive subseries (Gameboy and SNES specifically). They're actually not hard to get if you just want the carts.
Worlds of Ultima has a problem in that the second game in the series was never released on CD ROM or in any compilations, and you need the documentation. The first game was included in some collections, but I don't know how good the documentation is on those collections.
Ultima Underworld both of them were released on CD several times, most notably in the collection "The Ultimate RPG Archives" whcih is very good, but will probably run $50-$100 on eBay. (Get a disc-only copy--it includes digital backups of the documentation so you can just print it all off if you don't have the book).