May depend on your exact dates, but you should be able to. PP pictures are good in your account for 45 days from the date taken. If you wait until day 45 to start downloading (you can do edits before then) you will have 30 days to download and take additional pictures. That gives you roughly 75 days that one MM should cover. If the time from the beginning of one trip until the end of the other is longer than that, a cheaper solution could he doing the photo extension on the first portion if your trip ($20 I think for a 2 week extension). That would give you 89 days instead of the 75.
