Generally when you set out to do an expansion for a game, the first thing you do is make sure you've got the rights to do it. Which means checking to make sure you've still got the rights or signing a licensing agreement with whomever it is that owns the rights. And chances are that at that stage you also find a distributor to finance the project.

In this case, the answer to that would almost certainly be either 3D Realms or the distributor. But you'd really have to go back and look through the records from the bankruptcy proceedings because anything of value will typically be sold off to pay any creditors that might be owed money.

I have original CDs for all of the D3D expansions and they are a technical can of worms to install. For starters, the Blizzard installers have a Turbo-Pascal bug that causes fatal errors when run on anything past a Pentium II. You need to have an original Duke Nukem Plutonium Edition installed. The installers overlay Build code with a program called GAMER. Then you use GAMER to switch between versions. I have some downloads that are hacked versions to run with Jon Fowler WinXP converters. My hat would be off to anyone who could make it through all the technical and licensing issues. It would be worth it because Duke It Out in DC and Caribbean Vacation are real masterpieces.

Use unpackssi by JonoF to extract the expansion ssi files.

http://www.duke4ever.eu/index.php?view=d3d_jf_addons
http://www.jonof.id.au/misc

Then once you've got that done you can use the extracted files with eDuke32 or JonoF's JFDuke3D.

All the Official Addons are legal, except Duke: Nuclear Winter. Duke it Out in DC, and
Duke Carribbean Life is a Beach are Legal to give a copy to a friend. Any addon made by
Sunstorm is freeware.

http://forums.duke4.net/index.php?showtopic=2231&st=30&start=30

there abandon-ware not freeware the rights holders never surrendered the add-ons for free download the rights holder still has a copyright claim but is not persueing them for software that old. the issue with the addons is the fact that they had to run swicher programs that renamed the data files you wanted to use and the other files the major bug is dosbox being unable to run the rename script and not corrupt the data files. 3DR allowed sunstorm to sell these TC packs at retail but does not support them and will probably never distribute them unless the creators wish to have them reissued. the SW pack was a completed but canceled sunstorm expansion pack that was recovered and given to 3DR to post as a download.