Hey,
I'm an M1 in a LDR ... hopefully I can present you with some advice from the "other side" of things. First off, despite how well your partner prepares for school, there is no way to fully appreciate how difficult and time-consuming med school can be until you're actually in it. Any transition is difficult ... and med school is no exception. That being said, I think it's great that you're taking steps to prepare for this big change.
My bf and I had only been dating 3 months before I started school. Crazy - perhaps. But we're both in our late 20s and we met on E-Harmony. We knew what we were looking for in a partner and we decided that our relationship was worth fighting for. It's important that both people are willing to make the commitment, otherwise it won't work. Yes, I may be the busy med student, but his life can be just as crazy at times and it is essential that we can respect and appreciate one another. Medical school does NOT trump your feelings and activities. That being said, here are a few good (albeit nerdy) ways that my bf and I have attempted to bridge the divide.
1. video chat is KEY ... Skype has been fantastic. It's free AND you can use a webcam. We used to plan date nights where we would make dinner and watch a movie over Skype. We also had regular Skype-chats and he would leave me occasional video messages that I would find in the morning before I went to class. Always made me smile.
2. never underestimate the old school. Snail mail never goes out of style ... and receiving cards/cookies/care packages/flowers in the mail would brighten even the worst of days.
3. be creative. do what you enjoy doing - make a scrapbook, knit a scarf, whatever. It's the thought that counts more than anything. My bf cross-stitched me a pillow that says [bf's name] heart (literally a pic of an anatomical heart) [my name]. Perhaps he shouldn't give up his day job to be a professional cross-stitcher, but it was truly the most endearing thing anyone had done for me. It took some serious effort and time on his part.
4. check out this site for more ideas ... too many to list here:
http://www.lovingfromadistance.com/thingsforldrcouplestodo.htm
And last word of wisdom I'll impart. Visiting is great, but it can also be tense. You haven't seen each other for a while and expectations can be high. Sometimes you'll end up spending most of the visit bickering over stupid stuff or fighting for time together. Remember, even though you're taking 2 weeks to go visit, school and exams don't stop. Your partner still has to study and keep on top of their stuff in order to not fall behind and get more stressed out later. It's a juggling act for sure, but a relationship founded on respect and mature love can certainly push through the LDR.
Best of luck!