Is there a chance to have them run with UnrealTorunament?
no there is no way to make them work all for UT maybe some from RTNMappack can be fixed but not Caveescape maps.
1 used texture format DXT5 is not compatible with UT
2 total points in the maps exceed the value that editor 2.0 can handle
3 some other stuff wont work on UT
this maps below will normally run on UT
Caveescape.unr yes (can easy be fixed)
the reason I did not count in to be compatible with UT is : why should I create maps for UT-COOP no one play COOP within the UT community I did run 2 years a coop server and I did not seen 1 player connected to it so I stick to Unreal who runs in a way a lot better than UT as a lot stuff been updated on the new patch that will be released asap by Old Unreal team.
to be continued... new maps coming soon