>If I have an index on UPPER(Field) and then do a LOCATE FOR UPPER(Field) = lcField, does Rushmore take advantage of that index?

Check in the help under Rushmore. You should find an entry about Rusmore optimizable expression.

Also, look at the SYS(3054) which will tell you exactly how Rushmore is being used. It's not always safe to assume something is being optimized. Nor is always safe to assume you _want_ optimization.