i second that. it is required you do at least one month. and it probably should be at your home program, since some places require a letter from your chair.
although, aways are great experiences. id probably do one away additionally, just to see what a different program is like. one of the places i rotated at had a lot of their students wanting ortho... i suspect that was because it was a great program (nice residents, faculty, lifestyle, etc). it kind of sucks for those students because they are led on thinking ortho is like that everywhere.
most people ive run into do 2 aways. some do 3. ive heard of 4, but that seems excessive (not to mention pricey). your numbers are solid. doing one elective is probably enough.