Will you be happier with the midwife or will you be ok with going with someone you felt like you were "settling" with?
Questions/Thoughts:
If everything is going smoothly with the pregnancy the distance should not be a big deal, but if something changes I would switch to a closer choice.
Is cost a big worry, would the extra gas cost break the bank then I would think of picking someone closer... if it is just going to be an added cost but could afford it I would pick the one I wanted.
Does your little one travel well, some kids love car rides (or at least do not mind them) while others scream the whole time. Also while at the appiontment is there someone who can hold your child while you are busy with the midwife (some places a nurse or similar will hold the child or keep the little one occupied in the same room with you during the appiontment).
Make sure to have a more proactive birth plan on factoring in that 45 min drive, so when do you go in when in labor. Also have a backup for if the labor goes quickly what is the backup place to go and would the midwife make the trip up.
My OBGYN & hospital I picked was 30 mins away... this OBGYN was someone I have seen since I was in college so I really did not want to change, she is whom I felt most comfortable with. Now I did not have a toddler in tow but if I did I would still go to the person whom I felt the happiest with and who offered what I wanted. If I was to get pregnant again I would have to pick someone closer because it would be a high risk pregnancy (I had heart issues during labor/end of pregnancy).