Just having a "#!/bin/tcsh" or similar statement available at the start of the CSH script in conjunction with making the script executable solved the problem for me. I could directly call the CSH script from bash in this case.
As an example, I had to run tools.csh from a bash script called setup.sh. I did something like this in the bash script:
if [ -z \`head -1 tools.csh | grep '^#!'\` ];
then
TCSH=\`which tcsh\`;
echo "'#!'$TCSH" > tools.csh.temp;
cat tools.csh >> tools.csh.temp;
mv tools.csh.temp tools.csh;
fi;
chmod 755 tools.csh;
./tools.csh
# now I have all the setenv commands effective ...
