I concur with a lot of SoMinty's observations. Each ophthalmology residency admissions committee is run in a unique why by individuals with their own methodology for evaluating applicants for potential interviews, so you never know what the admissions committee member (who is probably a busy clinician/researcher/institutional leader) will pick up and fixate on while scanning rapidly through your app, and there are no hard and fast rules about what matters. The most you can do it put down things in your app that have the opportunity to reflect what you want and hope that someone bites, without having an expectation that everyone (or even anyone) will. If possibility alone is not worth enough to you personally to justify the expense then don't pay the price to have it in your application.
In my experience, I did one away in the same region as my medical school (not Texas or Cali), and I feel that I performed well and left a positive impression. However, it was definitely stressful and I can see how one wrong move could have resulted in a bad impression. Takeaways from that experience:
1) An interviewer at another program asked outright what they could do to woo me away from the above program, which implied that they thought that doing that away did imply strong personal interest. You can see how this interpretation could "hurt your standing" with other programs. But most programs didn't mention the away, so it's another item that may be fixated on or ignored along with your hobbies, permanent address, personal statement, etc.
2) I feel that doing the away at the above program was influential in me getting an interview there, and I have gotten the very subjective impression that programs do tend to interview applicants who did an away rotation at their specific program. So if you are interested in a program in particular (maybe close to your friends/family) then you might consider doing that away.
3) You could definitely hurt your chances if you rub someone the wrong way, but I actually didn't feel like doing poorly at the above away would have hurt my chances with any other programs (though ophtho is a small community), so the risk is usually finite. However, if you hit it off with people there and/or are generally able to show that you are a sociable person and work well in a team then it might go a long way in a positive way. Interviews exist in part to look for personality fit so if you can show beforehand that you get along well with everyone then it's a plus. Imo, aways are less about blowing people away with how smart you are (extremely unlikely) and more about being helpful, easygoing, and sincerely interested in learning about the institution while you're there. Strategies for doing well on aways are discussed extensively elsewhere, but my bottom line for this is, if you are a likeable, reasonably intelligent person and don't **** up then it is likely to help, but if you are a person who "takes time to warm up to people" (and hopefully at this point in life you know which one you are) then maybe you should not go on an away at a program that you are really interested in (though it may still be helpful to put it in your application that you went on an away in a specific area).
4) Aways are really informative for you professionally in showing you how other programs operate and which factors actually influence resident training/day-to-day life, so at I would recommend at least one away in general.
Other impressions from my application cycle:
5) Though interviewee groups did tend to include large numbers of Texas medical school students, Texas seemed very Midwest friendly. It is also not as great of a location as California and they more often find themselves in the position of convincing applicants to come to their program *in spite of* their location in Texas, so, subjectively, Texas seems easier to match into without hardcore connections than California.
6) I got several California interviews without any connections to the state on paper (have family in the area), though I was asked about personal connections during interviews. Meanwhile, I know a very competitive now-resident who wasn't invited to interview in California despite being a California native.
7) Applications (and MEDICAL SCHOOL) are expensive so consider the cost of aways within that context.
My takeaways:
1) Aways are informative for various reasons, so at least one is recommended
2) Do fewer (0-1) if you are awkward/asocial/a dick, more (1-3) if you are a nice person/good team player
3) An away can be more likely to get you an interview at a particular program (presuming the latter in #2)
4) Texas may be easier to get than California
5) How many interviews you get mostly depends on the strength of your application
6) Location biases (to permanent address, medical school, away locations, etc.) are super arbitrary and it's basically impossible to tell which programs will care and which won't, and in fact each applicant's experience with even one particular program is probably variable.