My train from Barcelona took me to Montpellier, France – from 8:45 to 13:30 or so. Once I was at Montpellier, I had to figure out how to get to Arles – it’s a stop on the train to Marseille, so that seemed easy enough.
Montpellier is a fairly small town, but it was incredibly busy – it’s a university town, and at the time it was chocked full of students and their parents it seemed. I asked at the information booth what I needed to do to get to Arles – I was told I needed a reservation, so I went to the ticket counter to get one. There I was told that a reservation was not needed! Just hop on the train that says “Arles” at 15:30 – Okay I said (this time the person spoke english, so it was more clear) – and I wandered around a bit.
There were no trains that said Arles near that time, so, I went back to the information booth and asked again – I was assured again that I do need a reservation! Back to the ticket counter. I got some help from another person, who said I did indeed need a reservation, and that I had missed the 15:30 train, but that I could get on a 17:04 train – because of the miscommunication she gave me a first class reservation for free, and I got to check out Montpellier in my newfound time, excellent!
I enjoyed Montpellier quite a bit – a bit too much though, I found myself thinking I knew where I was 20 minutes to my departure time – and ended up going in a few good circles, and then finding that I didn’t have small enough change to purchase a tram ticket! With the help of some nice locals, I found out how to get to the train station on foot (up a bunch of stairs, with my backpack on – oof!) and I got to the platform with 3 minutes to spare, no problem! 
One of two tram lines that run in Montpellier
Of course, I took some photos while I was there, and my GPS unit is still working like a charm! Check out the photos on a map here, and you can see what I saw!