I did the sutton summer school at nottingham last summer and i really enjoyed, it was a 2 hour train from where i live and it was my first time going there but i found it fine, sutton trust also reimburse your travel costs after which is good. one thing i realised is you will be with other subject strands so you will meet lots of people on other subejcts as well as yours, during the morning you have your subject lecures as if its actual uni so you learn the kinds of things you would learn on the course and you meet lecturers and students which is great, in the afternoons you go back to the accomdoation and eveyone kidna has free time to play sports or other games so its really enjoyable dont worry about it too much.