[TomTom]

I did say port/copy. Experimentally (tested with mp_beach) the nodes and connections appear possible to port (granted a small number of flags to be corrected). Actions etc. are very screwed up.
So a suggested recipe (experimental) would be;
1- Verify that the map origins are the same in ET and RTCW. It is not worth doing if you have to move every node.
2- Wipe out all the actions and routes in the rtcw waypoint editor.
3- Save the nav file (assumes you backed up beforehand any rtcw wip). Then move it to your fritzbot\bots\map directory.
4- There seems to be a rev flag at pos. 10 in the file (03-rtcw 07-et) which may optionally be changed with a hex editor.
5- The nodes may possibly be opened with Hobbits et waypoint editor but expect some errors messages (index...). Saving may also be problematic (path..) but I seem to sometimes be able to fool it into saving.
6- backup your experimental nav file.
7- open the map in ET and enable the editor then vid restart to verify the node placement.
8- if it looks good, try /node_save
9- Now see if it will load in Hobbits tool without error messages.
10- if ok search the node flags and correct them as needed. (or do it in the game console)
11- save and re-start ET, and one by one functionally copy the actions and routes as seems reasonable keeping the same action IDs. (you need to have both games open).
12- Finally correct for any differences between the ET and RTCW maps and add stuff for cvops etc to do. Test and modify to bring the play up to ET standards.

Granted if the recipe works it is not a huge time saver and not for novices.

If I had exact file format specs I could program a full converter (including actions and routes) but as I said before I could not test it properly unless I went out to buy a copy of rtcw.

Standard disclaimer: Stunt driver on closed track. Drive at your own peril.