I did prelim at UPMC (pittsburgh main). It's known as a tough program, but I didn't find it too challenging, and I learned a ton of medicine. I did 7 call months, and averaged 60-65 hours a week on those rotations. My hardest month was inpatient oncology, and that was higher, closer to 65-70 hours a week. I worked >80 hours (81) one time, and that was b/c my resident was being a hard ass about days off. 40-45 hours a week on the electives (GI, hematology), and I hardly showed up for radiology (2 hours a day). The ED months were 45-50 hours a week, and night-float (2 x 2 weeks) was 60 hour/weeks, with weekends off. But, I did have a VA intensive schedule, and those months are easy at UPMC.
In Pittsburgh, UPMC Shadyside is a little bit easier, Mercy is super cush, West Penn is not too bad.
Easy programs: Roanoke, VA, St. Joseph in Houston, Oakwood (Jokewood) in MI, St. Joseph in Phoenix, Good Sam's in Phoenix, the Denver program, Evanston Northwestern, Mayo Scottsdale and Jacksonville, Riverside in Columbus, OH, Philly has a few cush ones but I forgot the names. There is a lot out there. Some prelim medicine years are as comfortable as TYs. And, I don't think easy = no learning. The cush programs just cut out the BS, and you still get to learn medicine.