hmmm.... don't know if anyone is willing to touch a question like this on this board!

I don't think there is an accurate way to answer this question. Every diocese is made of a spectrum of Catholics, from daily communicants to C&E Catholics, from praise and worship to Gregorian chant in the EF only, from Catholics who believe all that the Church teaches in the Catechism to those believe this-that-or-the-other-doctrine must change. Does this person have in mind the bishop of the diocese? Bishops change with some regularity while the population of the people in the pews take longer to change demographically.

I don't think this should be a criteria for where to move. Rather, I think your friend should try to find a parish home near a prospective employer where the mass is truly Catholic and the faith is solidly taught.

I would reframe the question as such-
Are there dioceses that have at least one ecclesial community (church, monastery, basilica, cathedral) that displays a requisite amount of respect towards authentic liturgical philosophy and praxis throughout the categories of options and rubrics in prevalent documents? And has that church's influence had a noticeable, tangible endorsement by its bishop as exemplary to the rest of the diocese?
One could obviously use St. John Cantius in Chicago, or St. Edward's in Newark, CA. as such locales.
But as long as a diocese seems to maintain a "missalette mentality" that is proven by the number of parishes that subsribe to the throwaways, the issue of conservative/liberal or orthodox/progressive is moot. YMMV.

Employing 'conservative' and 'progressive' as terms to discern genuine musicianship and liturgical solemnity can sometimes mislead. Cambridge, Massachusetts is often acclaimed as the most "liberal" community in the United States, yet St. Paul Church (home to the Harvard Student Center and the Boston Archdiocesan Choir School) thrives there. The parish is liberal in that its parishioners are independent thinkers, but they are nonetheless diligent in maintaining high muscial standards and correct liturgical observance. Harvard University always gets a knee jerk response as being liberal, yet Michael Novak, Alan Keyes, Avery Dulles and a host of other conservatives and moderates are among its graduates. (And let's not forget Olbash the elder.)

I've yet to be convinced that even a bishop's leanings determine local attitudes. Life is a bit more complex and therefore what happens within a diocese reflects that.

"...make sure the pastor had the orientation I was looking for and the leadership ability to back up a good music program."

A good point, to which I would add: You might also determine the general policy of the diocese concerning priest rotation, and, as far as possible, how long your good pastor might expect to remain in his current parish. Unless you are prepared to move with him (which some musicians have done).

Remember, too, that "conservative" does not necessarily equal "more traditional". Conservatism may just as easily be a staunch adherence to the status quo (a missalette in every pew; Glory and Praise on the organ...). These days, advocating the traditional is a very progressive thing to do.