I'm a second year law student who lived in wolfson house last year and will be going back this year. GDS and wolfson house will have an overwhelming majority of students based at guy's campus, however you can expect about 25% to be based at the strand. This varies from flat to flat, but this was my experience last year. And as for buses, they take about 15 minutes depending on the time of day, though you will probably find that you end up walking most of the time.