Agree with the above. I did externships at USC, Parkland, LSUNO, and UAB. I enjoyed all of them a lot and am now a resident at Parkland. Our externs are in the clinic or OR and take call with the residents (we usually won't make you stay overnight on a tooth call night or will call you if something comes in). I haven't been to LSUShreveport but have heard great things about their externship.
I recommend going to programs you are genuinely interested in. Externships are important for applicants to know what each program does in terms of scope, how much the residents operate/do in the OR, and get a vibe of the culture. Of course you want to pull teeth, do some tori reduction, and get your hands dirty, but you WILL do it day in and day out as an intern and should use the opportunity to learn about where you want to train. Ultimately, I got interviews where I did externships and was able to talk about my experience.
My experiences:
LSU NO was amazing. I was able to stay in the University Hospital at the time which was prior to the new hospital opening. Lived in the hospital call room for two weeks and really enjoyed the program culture, scope and how much they did. Cons were the city which I didn't spend much time in.
Parkland was awesome. I had to get an airbnb which was an added expense, we don't have externs stay in the call room. I was able to spend half the time in the clinic and half the time in the OR. Was able to do some stuff in the OR which was great too. Cons are mentioned above with having to pay for a place, but ultimately I ranked it one and matched; and am very happy with my choice.
Oral and Maxillofacial Surgery Internship and Externship
USC was a busy outpatient clinic and where I went to dental school. I was able to take teeth out and enjoyed that experience, and had a place to stay since it was close to home. The cons would be having to pay for a place to stay as well.
UAB also had a placed to stay (old abandoned call rooms in the tower). Their resident clinic is attached to the dental school clinic and had a lot of opportunity to get my hands dirty. Also got a lot of face time with faculty since they were there in the clinic as well. I enjoyed Birmingham a ton and they had amazing residents who really taught me a lot, eventually letting me stay in one of their condos which was really cool.
I've noticed a trend of more and more people does one week externships, I personally think two weeks is a better idea if you have genuine interest in the program you're going to. If you just want to see as many places as possible, one week would give you the flexibility. But it's hard to be as impressive in just one week in my opinion.
I would personally recommend any of the above and am happy to answer DM's about my experience.