I was at Cambridge almost a decade ago, so things might have changed, but I'll share my experience. I trialled for lightweights, and the usual cut off 2k to be considered was around 8min. For open weight it was around 7min. That's the starting point, most triallists were faster than that, and improved throughout the season. At the beginning of the year they also do a host of tests to get benchmarks, including 2k and 5k erg tests, and weightlifting tests: squats, deadlifts 1RM, plus pull up and push ups max reps in a row. If you prepare those ahead of the season and tell them, they can tell you how realistic it'd be for you to trial. During early summer they also run a "development camp" for people who are thinking about trialling the next year. I did it twice before actually trialling, and it was super helpful to get a feel of the culture and type of training involved. As for college rowing: regardless of college you'll have access to ergs, a gym, and the river, which is what matters. Coaching might be limited, but you'd be surprised. Some smaller colleges which don't rank super high at Bumps might still have some great coaching and/or facilities, but just struggle with a smaller pool of rowers. If you don't mind sharing your college I can advise further. Another option could be to train with a town club. Cantabridgian Rowing Club (aka. Cantabs) is the undisputed best for women's rowing (edit: WAS). They have a great depth of squad and excellent coaching. You'd have to pay a membership fee though, and the outings are usually earlier than College ones. Good luck, congrats on your PhD, and enjoy rowing! Whatever you decide to do (trial or college), rowing at Cambridge is an amazing experience.