RtCW full MP 1.0/1.1
In 1.0 I found servers with the regular gamespeed and also rediscovered Tweaked servers as we called it back in the days.. So kewLL.. In most cases of this fast gameplay, also the fast dropreloading is used by everybody. I had not used Dropreload in about 7 or 8 years and I liked it.. :) The customised RtCW copy I got from a friend included a simple dropreload script and looked more fancy than my own from 10 years back so only thing to do was to bind that to my reloadbutton. To do so: First use Notepad to edit the dropscript.cfg to the key you prefer. Than, during the game goto console by typing: ~ . Type: /exec dropscript
Note that in some servers dropreload is handy (enabled) and in others it doesn't work (it will nog fill up with bullets), so in last case just bind your normal reload again via the menu ingame.
QuickStart: Just download a version or find a CD 1.0 and install. May be a simple as getting a folder to plant between your Program Files. If theres an extra folder in your install called Mapdownloader (DLL-injector) no worries, having this loaded provides faster downloads if there are packs like maps needed. But whatever version/installer, set networksettings and check for servers. Why not. :)

RtCW full MP 1.30,1.31,1.32
One of latest updates for 1.0 seems to be PunkBuster for 1.0 = Sandmod 2.x, which exists since 2009. With this update (referred also as 1.3 update) it's possible to join 1.3 servers (sometimes even with PB itself disabled in the game).
In time many installs have been updated up to the point that would check the CD-key. Others like me did not wish to update, as it used other serverlist and players and this annoying PunkBuster that was part of Wolf 1.33 and up. So many players did not update to 1.33 or 1.4 at all. And all those that díd try to update their Wolfy ran in big game horror. I was one of them too. If you bought a 1.3 version, you can downgrade it to 1.0 but I never understood why one would >:] .. It seems a better idea to copy the Program folder and update one of them to 1.4 (can't do that afaik ;) and always remember that several copies of 1.0 and 1.4 are online. I found out no CD-key or crack was needed for 1.0 and 1.3 copies, but with your 1.4 it's wise to keep in mind that when problems occur with joining servers, this might have to do with permanent bans on a bad seriakey. So IMHO it's best to BUY Return to Castle Wolfenstein (1.33 or higher) as it's the best FPS ever, get yourself a copy - and have 2 different working versions of RtCW!
Do note that few servers demand this PunkBuster/Sandmod 2.x/RtCWupdate1.3 anti cheat protection to be installed. Most seem to be 1.3 servers compatible with 1.0.
Btw.. Mac users would be able to use these downloads to add PB to RtCW 1.0. I wonder.. Maybe if they would, they might be able to join servers running it and also 1.3 servers. But.. Apple users probably still miss a master patch so need to use a workaround atm. Or use a Win32Shell that supports OGL.

RtCW full MP 1.33 (GotY)
Latest Master Patch for 1.3 seems to work for all 1.3x versions. For instance the Game of the Year edition (which is 1.33) but also 1.0 with the Mancual 1.33 update will show the servers after applying this Master Patch. The game of the Year version (1.33) has extra maps compared to an updated 1.0: GotY Mappack. Note RtCW for Xbox was also a v1.33, and that's about all I know about Xbox.