I just took my step 1 and did very well (260+). I'm also the kind of person who needs a lot of repetition, but I really wouldn't worry too much about reviewing during summer after first year...you really need the break at this point because second year can be killer.
I reviewed material from first year as I went through second year. For example, if we were learning about pulmonary path/clinical medicine, I would review pulmonary physio from first year, usually just by reading the appropriate chapter in BRS Physio. I would also do some anatomy for the organ system we were currently working on. The material really sinks in if you review it while learning about the disease processes during second year. I'd say that second year is when I really learned physio and anatomy.
In summary, take this last month of your summer off and enjoy it, since it's the last one you'll ever get. Do something fun so that you can preserve your sanity for second year (and third year, fourth year, residency, fellowship...).